diff --git a/apps/st/package.json b/apps/st/package.json
index 7ae6c9f53..3919123ff 100644
--- a/apps/st/package.json
+++ b/apps/st/package.json
@@ -41,6 +41,7 @@
         "chart.js": "^4.4.8",
         "chartjs-plugin-zoom": "^2.2.0",
         "dayjs": "^1.11.13",
+        "decimal.js": "^10.6.0",
         "js-cookie": "^3.0.5",
         "jszip": "^3.10.1",
         "lucide-react": "^0.474.0",
diff --git a/apps/st/src/components/module/CompactDataGrid.tsx b/apps/st/src/components/module/CompactDataGrid.tsx
index fad888a5f..7ffbaa1b3 100644
--- a/apps/st/src/components/module/CompactDataGrid.tsx
+++ b/apps/st/src/components/module/CompactDataGrid.tsx
@@ -7,6 +7,7 @@ import { RealGridReact, RGDataColumn } from "realgrid-react"
 import type { CellStyleCallback, CellStyleCallbackParams,CellStyleCallbackResult, DataGridProps, FooterItemWithCallback, GridViewWithSetColumns, RealGridColumnInfo } from "../type/DataGrid.type"
 
 import { getComputedValueCallback } from "@/components/util/grid/computedFieldCallbacks"
+import { wrapWithFormatTruncate } from "@/components/util/grid/decimalNumber"
 
 function mergeCellStyleCallbackResult(
     baseStyleName: string | undefined,
@@ -32,7 +33,7 @@ declare module "realgrid" {
         setOptions(options: {
             footer?: { visible?: boolean };
             summaryMode?: 'aggregate' | 'statistical' | 'none';
-            checkBar?: { visible?: boolean };
+            checkBar?: { visible?: boolean; checkableOnly?: boolean };
         }): void;
     }
 }
@@ -49,10 +50,11 @@ type GridViewWithCheckApi = GridViewWithSetColumns & {
     checkItem?: (itemIndex: number, checked: boolean, exclusive?: boolean) => void;
     checkRow?: (dataRow: number, checked: boolean, exclusive?: boolean) => void;
     checkAll?: (checked: boolean) => void;
+    setCheckable?: (itemIndex: number, checkable: boolean) => void;
 };
 
 /** columnInfo → RealGrid DataField 배열 (computed → valueCallback 포함, setFields용) */
-function buildFieldsFromColumns(columns: { fieldName: string; valueType?: ValueType; computed?: import("../type/DataGrid.type").ComputedFieldConfig }[]) {
+function buildFieldsFromColumns(columns: { fieldName: string; valueType?: ValueType; dataFormat?: string; computed?: import("../type/DataGrid.type").ComputedFieldConfig }[]) {
     return columns.map((col) => {
         const field: { fieldName: string; dataType: string; valueCallback?: (prod: unknown, dataRow: number, fieldName: string, fieldNames: string[], values: unknown[]) => number } = {
             fieldName: col.fieldName,
@@ -68,7 +70,7 @@ function buildFieldsFromColumns(columns: { fieldName: string; valueType?: ValueT
             const hasSumOfMaxGroups = "groups" in col.computed && Array.isArray(col.computed.groups) && col.computed.groups.length > 0;
             const hasSumPerTenThousand = col.computed.type === "sumPerTenThousand" && "numeratorFields" in col.computed && col.computed.numeratorFields.length > 0 && "denominatorField" in col.computed && Boolean(col.computed.denominatorField);
             if (hasFields || hasNumeratorDenominator || hasMaxOfFieldAndSum || hasDifferenceOfSums || hasHalfSumOfSums || hasSumOfTwoHalfSumOfSums || hasSumOfMaxGroups || hasSumPerTenThousand) {
-                field.valueCallback = getComputedValueCallback(col.computed) as (prod: unknown, dataRow: number, fieldName: string, fieldNames: string[], values: unknown[]) => number;
+                field.valueCallback = wrapWithFormatTruncate(getComputedValueCallback(col.computed), col.dataFormat);
             }
         }
         return field;
@@ -138,6 +140,7 @@ const CompactDataGrid = ({
     onRowClick,
     onItemChecked,
     onItemAllChecked,
+    checkableCallback,
     compactFullWidth = false,
     compactGridHeightClass = "h-[55vh]",
     headerHeight = 60,
@@ -147,9 +150,11 @@ const CompactDataGrid = ({
     const columnsRef = useRef(columns);
     const rowDataRef = useRef<Record<string, string | number>[]>(rowData);
     const cellStyleCallbackRef = useRef<CellStyleCallback | undefined>(cellStyleCallback);
+    const checkableCallbackRef = useRef<DataGridProps["checkableCallback"]>(checkableCallback);
     columnsRef.current = columns;
     rowDataRef.current = rowData;
     cellStyleCallbackRef.current = cellStyleCallback;
+    checkableCallbackRef.current = checkableCallback;
 
     useLayoutEffect(() => {
         if (!cellStyleCallback || !gridRef.current?.gridView) return;
@@ -178,8 +183,10 @@ const CompactDataGrid = ({
             try {
                 checkGrid.checkAll?.(false);
                 rowData.forEach((row, itemIndex) => {
+                    const checkable = checkableCallbackRef.current?.(row, itemIndex) ?? true;
+                    checkGrid.setCheckable?.(itemIndex, checkable);
                     const checked = checkByRowFlag((row as Record<string, unknown>).__checked);
-                    if (!checked) return;
+                    if (!checked || !checkable) return;
                     if (checkGrid.checkItem) {
                         checkGrid.checkItem(itemIndex, true, false);
                         return;
@@ -276,7 +283,7 @@ const CompactDataGrid = ({
 
         // 헤더 체크박스 표시 여부 설정
         gridView.setOptions({
-            checkBar: { visible: showHeaderCheckbox },
+            checkBar: { visible: showHeaderCheckbox, checkableOnly: true },
             rowIndicator: { visible: false },
         });
 
@@ -499,6 +506,7 @@ const CompactDataGrid = ({
         compactFullWidth,
         compactGridHeightClass,
         headerHeight,
+        checkableCallback,
     ]);
 
     // 행 클릭 이벤트
@@ -527,6 +535,17 @@ const CompactDataGrid = ({
 
         if (onItemChecked) {
             gridView.onItemChecked = (_grid, itemIndex, checked) => {
+                const row = rowDataRef.current[itemIndex];
+                if (
+                    row &&
+                    checkableCallbackRef.current &&
+                    !checkableCallbackRef.current(row, itemIndex)
+                ) {
+                    if (checked) {
+                        (_grid as GridViewWithCheckApi).checkItem?.(itemIndex, false, false);
+                    }
+                    return;
+                }
                 onItemChecked(itemIndex, checked);
             };
         } else {
diff --git a/apps/st/src/components/module/DataGrid.tsx b/apps/st/src/components/module/DataGrid.tsx
index e679a75fa..fea761a3f 100644
--- a/apps/st/src/components/module/DataGrid.tsx
+++ b/apps/st/src/components/module/DataGrid.tsx
@@ -24,6 +24,7 @@ import type {
 } from "../type/DataGrid.type";
 
 import { getComputedValueCallback } from "@/components/util/grid/computedFieldCallbacks";
+import { wrapWithFormatTruncate } from "@/components/util/grid/decimalNumber";
 import {
     buildExcelExportFileBaseName,
     buildFixedColumnNameSet,
@@ -251,7 +252,7 @@ declare module "realgrid" {
         setOptions(options: {
             footer?: { visible?: boolean };
             summaryMode?: "aggregate" | "statistical" | "none";
-            checkBar?: { visible?: boolean; exclusive?: boolean };
+            checkBar?: { visible?: boolean; exclusive?: boolean; syncHeadCheck?: boolean };
         }): void;
     }
 }
@@ -409,7 +410,13 @@ function reapplyListEditorsOnGrid(
 type GridViewWithCheckApi = {
     checkItem?: (itemIndex: number, checked: boolean, exclusive?: boolean) => void;
     checkRow?: (dataRow: number, checked: boolean, exclusive?: boolean) => void;
-    checkAll?: (checked: boolean) => void;
+    checkAll?: (
+        checked: boolean,
+        visibleOnly?: boolean,
+        checkableOnly?: boolean,
+        checkEvent?: boolean,
+    ) => void;
+    setAllCheck?: (checked: boolean) => void;
 };
 
 function isRowCheckedFlag(value: unknown): boolean {
@@ -689,26 +696,6 @@ function sortRowsGroupPreserving(
 }
 
 /** columnInfo → RealGrid DataField 배열 (computed → valueCallback 포함, setFields용) */
-function getDecimalPlacesFromDataFormat(dataFormat?: string): number | null {
-    if (!dataFormat) return null;
-    const match = dataFormat.match(/\.(0+|#+)/);
-    const decimalToken = match?.[1];
-    if (decimalToken) return decimalToken.length;
-    // #,##0 등 정수 포맷 — 소수부 없음 → 0자리 절삭(내림)
-    if (/[#0]/.test(dataFormat)) return 0;
-    return null;
-}
-
-function truncateByDecimalPlaces(value: number, decimalPlaces: number): number {
-    if (!Number.isFinite(value)) return 0;
-    if (decimalPlaces < 0) return value;
-    const factor = 10 ** decimalPlaces;
-    const scaled = value * factor;
-    // 절삭(truncate): 반올림 없이 소수점 이하를 버린다.
-    const truncated = scaled >= 0 ? Math.floor(scaled) : Math.ceil(scaled);
-    return truncated / factor;
-}
-
 function buildFieldsFromColumns(
     columns: {
         fieldName: string;
@@ -823,33 +810,10 @@ function buildFieldsFromColumns(
                 hasQuotientRatioPercent ||
                 hasQuotientTimesMultiplierPercent
             ) {
-                const computedCallback = getComputedValueCallback(
-                    col.computed,
-                ) as (
-                    prod: unknown,
-                    dataRow: number,
-                    fieldName: string,
-                    fieldNames: string[],
-                    values: unknown[],
-                ) => number;
-                const decimalPlaces = getDecimalPlacesFromDataFormat(col.dataFormat);
-                field.valueCallback = (
-                    prod: unknown,
-                    dataRow: number,
-                    fieldName: string,
-                    fieldNames: string[],
-                    values: unknown[],
-                ) => {
-                    const computedValue = computedCallback(
-                        prod,
-                        dataRow,
-                        fieldName,
-                        fieldNames,
-                        values,
-                    );
-                    if (decimalPlaces == null) return computedValue;
-                    return truncateByDecimalPlaces(computedValue, decimalPlaces);
-                };
+                field.valueCallback = wrapWithFormatTruncate(
+                    getComputedValueCallback(col.computed),
+                    col.dataFormat,
+                );
             }
         }
         return field;
@@ -1047,7 +1011,17 @@ const DataGrid = ({
         if (!dp?.setRows) return;
         try { gv?.commit?.(); } catch { try { gv?.cancel?.(); } catch { /* noop */ } }
         dp.setRows(rowData);
-    }, [rowData]);
+        if (showHeaderCheckbox) {
+            const checkGrid = gridRef.current?.gridView as GridViewWithCheckApi | undefined;
+            isSyncingChecksFromRowDataRef.current = true;
+            try {
+                checkGrid?.checkAll?.(false, false, false, false);
+                checkGrid?.setAllCheck?.(false);
+            } finally {
+                isSyncingChecksFromRowDataRef.current = false;
+            }
+        }
+    }, [rowData, showHeaderCheckbox]);
 
     // highlightedRowId가 변경될 때 해당 행으로 스크롤 및 선택
     useEffect(() => {
@@ -1634,7 +1608,7 @@ useEffect(() => {
 
         // 헤더 체크박스 표시 여부 설정
         gridView.setOptions({
-            checkBar: { visible: showHeaderCheckbox, exclusive: false },
+            checkBar: { visible: showHeaderCheckbox, exclusive: false, syncHeadCheck: true },
             rowIndicator: { visible: false },
         });
 
@@ -2054,14 +2028,10 @@ useEffect(() => {
         gridView.refresh?.();
     }, [footerVerificationResult, columns]);
 
-    // 행 클릭 이벤트 + 검증 오류 셀 클릭 시 showMessage (공식 문서 방식)
+    // 행·셀 클릭 이벤트 (검증 오류 툴팁은 hover만 — onShowTooltip / 빈 셀 오버레이)
     useEffect(() => {
         const gridView = gridRef.current?.gridView;
-        if (
-            !gridView ||
-            (!onRowClick && !cellTooltipCallback && !onDataCellClick)
-        )
-            return;
+        if (!gridView || (!onRowClick && !onDataCellClick)) return;
 
         gridView.onCellClicked = (grid, clickData) => {
             if (
@@ -2082,46 +2052,6 @@ useEffect(() => {
                 ).getCurrent?.();
                 const fieldName =
                     cellIndex?.fieldName ?? cellIndex?.column ?? "";
-                // cellTooltipCallback 있으면 해당 셀 메시지로 showMessage (공식 문서: TooltipOptions + CellIndex)
-                // 빈 셀은 hover 오버레이로만 표시하므로 클릭 showMessage는 생략 (이중 표출 방지)
-                if (cellTooltipCallbackRef.current && row && cellIndex) {
-                    if (!isEmptyGridCellValue(row[fieldName])) {
-                        const msg = cellTooltipCallbackRef.current({
-                            row: row as Record<string, string | number>,
-                            fieldName,
-                        });
-                        if (msg) {
-                            const colName =
-                                columns.find(
-                                    (c) =>
-                                        c.fieldName === fieldName ||
-                                        c.name === cellIndex.column,
-                                )?.name ??
-                                cellIndex.column ??
-                                fieldName;
-                            (
-                                gridView as {
-                                    showMessage?: (
-                                        opts: {
-                                            message: string;
-                                            hideDuration?: number;
-                                        },
-                                        idx: {
-                                            itemIndex: number;
-                                            column: string;
-                                        },
-                                    ) => void;
-                                }
-                            ).showMessage?.(
-                                { message: msg, hideDuration: 5000 },
-                                {
-                                    itemIndex: cellIndex.itemIndex,
-                                    column: colName,
-                                },
-                            );
-                        }
-                    }
-                }
                 if (onDataCellClickRef.current && row !== undefined) {
                     onDataCellClickRef.current({
                         row: (row ?? {}) as Record<string, string | number>,
@@ -2139,7 +2069,7 @@ useEffect(() => {
         return () => {
             if (gridView.onCellClicked) gridView.onCellClicked = undefined;
         };
-    }, [onRowClick, onDataCellClick, cellTooltipCallback, columns]);
+    }, [onRowClick, onDataCellClick]);
 
     // RealGrid 네이티브 툴팁은 데이터 셀만 지원 → 빈 셀·총계 footer는 React 오버레이로 보완
     useEffect(() => {
@@ -2404,15 +2334,13 @@ useEffect(() => {
 
         const gridView = gridRef.current.gridView as GridViewWithCheckApi;
 
-        const hasCheckedColumn = rowData.some((row) =>
-            Object.prototype.hasOwnProperty.call(row, "__checked"),
-        );
-        if (!hasCheckedColumn) return;
-
+        // rowData 교체(조회/저장/제출/항목삭제) 시 헤더·행 체크를 해제한다.
+        // `__checked`가 있는 행만 다시 체크한다. 없으면 전부 해제 상태로 둔다.
         const timer = window.setTimeout(() => {
             isSyncingChecksFromRowDataRef.current = true;
             try {
-                gridView.checkAll?.(false);
+                gridView.checkAll?.(false, false, false, false);
+                gridView.setAllCheck?.(false);
                 rowData.forEach((row, itemIndex) => {
                     if (!isRowCheckedFlag((row as Record<string, unknown>).__checked)) return;
                     if (gridView.checkItem) {
diff --git a/apps/st/src/components/module/SplitDataGrid.tsx b/apps/st/src/components/module/SplitDataGrid.tsx
index d7e33ea9b..75f8d2988 100644
--- a/apps/st/src/components/module/SplitDataGrid.tsx
+++ b/apps/st/src/components/module/SplitDataGrid.tsx
@@ -16,6 +16,7 @@ const SplitDataGrid = ({
     leftCellStyleCallback,
     rightOnItemChecked,
     rightOnItemAllChecked,
+    rightCheckableCallback,
     enableSort = false,
 }: SplitDataGridProps) => {
     return (
@@ -39,6 +40,7 @@ const SplitDataGrid = ({
                 setRowData={setRightRowData}
                 onItemChecked={rightOnItemChecked}
                 onItemAllChecked={rightOnItemAllChecked}
+                checkableCallback={rightCheckableCallback}
             />
         </div>
     );
diff --git a/apps/st/src/components/module/TabDataGrid.tsx b/apps/st/src/components/module/TabDataGrid.tsx
index 4b6b14bbc..04b372333 100644
--- a/apps/st/src/components/module/TabDataGrid.tsx
+++ b/apps/st/src/components/module/TabDataGrid.tsx
@@ -44,6 +44,7 @@ function mergeCellStyleCallbackResult(
 import SplitDataGrid from "./SplitDataGrid";
 
 import { getComputedValueCallback } from "@/components/util/grid/computedFieldCallbacks"
+import { wrapWithFormatTruncate } from "@/components/util/grid/decimalNumber"
 import {
     buildExcelExportFileBaseName,
     buildFixedColumnNameSet,
@@ -252,7 +253,7 @@ function sortRowsGroupPreserving(
 }
 
 /** columnInfo → RealGrid DataField 배열 (computed → valueCallback 포함, setFields용) */
-function buildFieldsFromColumns(columns: { fieldName: string; valueType?: ValueType; computed?: import("../type/DataGrid.type").ComputedFieldConfig }[]) {
+function buildFieldsFromColumns(columns: { fieldName: string; valueType?: ValueType; dataFormat?: string; computed?: import("../type/DataGrid.type").ComputedFieldConfig }[]) {
     return columns.map((col) => {
         const field: { fieldName: string; dataType: string; valueCallback?: (prod: unknown, dataRow: number, fieldName: string, fieldNames: string[], values: unknown[]) => number } = {
             fieldName: col.fieldName,
@@ -268,7 +269,7 @@ function buildFieldsFromColumns(columns: { fieldName: string; valueType?: ValueT
             const hasSumOfMaxGroups = "groups" in col.computed && Array.isArray(col.computed.groups) && col.computed.groups.length > 0;
             const hasSumPerTenThousand = col.computed.type === "sumPerTenThousand" && "numeratorFields" in col.computed && col.computed.numeratorFields.length > 0 && "denominatorField" in col.computed && Boolean(col.computed.denominatorField);
             if (hasFields || hasNumeratorDenominator || hasMaxOfFieldAndSum || hasDifferenceOfSums || hasHalfSumOfSums || hasSumOfTwoHalfSumOfSums || hasSumOfMaxGroups || hasSumPerTenThousand) {
-                field.valueCallback = getComputedValueCallback(col.computed) as (prod: unknown, dataRow: number, fieldName: string, fieldNames: string[], values: unknown[]) => number;
+                field.valueCallback = wrapWithFormatTruncate(getComputedValueCallback(col.computed), col.dataFormat);
             }
         }
         return field;
diff --git a/apps/st/src/components/statistics/input/PublicSewageFacilityInp.tsx b/apps/st/src/components/statistics/input/PublicSewageFacilityInp.tsx
index fa5892179..d6b4152cb 100644
--- a/apps/st/src/components/statistics/input/PublicSewageFacilityInp.tsx
+++ b/apps/st/src/components/statistics/input/PublicSewageFacilityInp.tsx
@@ -312,6 +312,28 @@ const PublicSewageFacilityInp = () => {
         return v === 1 || v === '1' || v === 'Y' || v === 'y' || v === 'true';
     };
 
+    const isSelfMappingTarget = (
+        row: Record<string, string | number>,
+        mainFcltSn: string | null,
+    ): boolean => Boolean(mainFcltSn) && String(row.fcltSn ?? '') === mainFcltSn;
+
+    const hasCheckedSelfMapping = (
+        rows: Record<string, string | number>[],
+        mainFcltSn: string | null,
+    ): boolean => rows.some((r) => isSelfMappingTarget(r, mainFcltSn) && isCheckedRow(r));
+
+    /** 왼쪽에서 선택한 시설을 오른쪽에서 본인 체크하면 다른 시설은 해제 */
+    const applyExclusiveSelfMappingChecks = (
+        rows: Record<string, string | number>[],
+        mainFcltSn: string | null,
+    ): Record<string, string | number>[] => {
+        if (!hasCheckedSelfMapping(rows, mainFcltSn)) return rows;
+        return rows.map((r) => ({
+            ...r,
+            __checked: isSelfMappingTarget(r, mainFcltSn) ? 'Y' : '',
+        }));
+    };
+
     const executeSubmit = async (submitInfo: StatisticsInputSubmitInfoFormData) => {
         const verificationBlocked = getVerificationPeriodActionBlockedMessage(periodCheckList);
         if (verificationBlocked) {
@@ -520,19 +542,36 @@ const PublicSewageFacilityInp = () => {
                     return;
                 }
 
-                const saveList: PublicSewageMainFacilityMappingSaveItem[] = rightRows
-                    .filter((r) => isCheckedRow(r))
-                    .map((r) => ({
-                        fcltSn: nullableTrimmedString(r.fcltSn),
-                        admdstCd: nullableTrimmedString(r.admdstCd),
-                        admdstNm: nullableTrimmedString(r.admdstNm),
-                        swtrmtFcltCd: nullableTrimmedString(r.swtrmtFcltCd),
-                        swtrmtFcltNm: nullableTrimmedString(r.swtrmtFcltNm),
-                        isMainYn: nullableTrimmedString(r.isMainYn),
-                    }));
+                const checkedRows = rightRows.filter((r) => isCheckedRow(r));
+                const exclusiveSelf = hasCheckedSelfMapping(rightRows, selectedMainFacilitySn);
+                const saveList: PublicSewageMainFacilityMappingSaveItem[] = (
+                    exclusiveSelf
+                        ? checkedRows.filter((r) => isSelfMappingTarget(r, selectedMainFacilitySn))
+                        : checkedRows
+                ).map((r) => ({
+                    fcltSn: nullableTrimmedString(r.fcltSn),
+                    admdstCd: nullableTrimmedString(r.admdstCd),
+                    admdstNm: nullableTrimmedString(r.admdstNm),
+                    swtrmtFcltCd: nullableTrimmedString(r.swtrmtFcltCd),
+                    swtrmtFcltNm: nullableTrimmedString(r.swtrmtFcltNm),
+                    isMainYn: nullableTrimmedString(r.isMainYn),
+                }));
+
+                const exclusiveDroppedSns = exclusiveSelf
+                    ? new Set(
+                          checkedRows
+                              .filter((r) => !isSelfMappingTarget(r, selectedMainFacilitySn))
+                              .map((r) => String(r.fcltSn ?? ''))
+                              .filter((sn) => sn !== ''),
+                      )
+                    : new Set<string>();
 
                 const deleteList = rightRows
-                    .filter((r) => String(r.mappedYn ?? '') === 'Y' && !isCheckedRow(r))
+                    .filter((r) => {
+                        const sn = String(r.fcltSn ?? '');
+                        if (String(r.mappedYn ?? '') === 'Y' && !isCheckedRow(r)) return true;
+                        return exclusiveDroppedSns.has(sn) && String(r.mappedYn ?? '') === 'Y';
+                    })
                     .map((r) => String(r.fcltSn ?? ''))
                     .filter((sn) => sn !== '');
 
@@ -1132,10 +1171,13 @@ const PublicSewageFacilityInp = () => {
             if (rawList.length === 0) {
                 alert('해당 시설은 중심처리시설의 위탁시설로 연결되어있습니다.');
             }
-            const mappedTargetRows = rawList.map((item) => ({
-                ...item,
-                __checked: item.mappedYn === 'Y' ? 'Y' : '',
-            }));
+            const mappedTargetRows = applyExclusiveSelfMappingChecks(
+                rawList.map((item) => ({
+                    ...item,
+                    __checked: item.mappedYn === 'Y' ? 'Y' : '',
+                })),
+                fcltSn,
+            );
             setRowDataMap((prev) => {
                 const next = new Map(prev);
                 next.set('MainFacilityTarget', toGridRows(mappedTargetRows));
@@ -1318,11 +1360,25 @@ const PublicSewageFacilityInp = () => {
                                                         const next = new Map(prev);
                                                         const rows = [...(next.get('MainFacilityTarget') ?? [])];
                                                         if (!rows[itemIndex]) return prev;
+                                                        const clicked = rows[itemIndex];
+                                                        if (
+                                                            checked &&
+                                                            hasCheckedSelfMapping(rows, selectedMainFacilitySn) &&
+                                                            !isSelfMappingTarget(clicked, selectedMainFacilitySn)
+                                                        ) {
+                                                            return prev;
+                                                        }
                                                         rows[itemIndex] = {
-                                                            ...rows[itemIndex],
+                                                            ...clicked,
                                                             __checked: checked ? 'Y' : '',
                                                         };
-                                                        next.set('MainFacilityTarget', rows);
+                                                        next.set(
+                                                            'MainFacilityTarget',
+                                                            applyExclusiveSelfMappingChecks(
+                                                                rows,
+                                                                selectedMainFacilitySn,
+                                                            ),
+                                                        );
                                                         return next;
                                                     });
                                                 }
@@ -1333,16 +1389,59 @@ const PublicSewageFacilityInp = () => {
                                                 ? (checked) => {
                                                     setRowDataMap((prev) => {
                                                         const next = new Map(prev);
-                                                        const rows = [...(next.get('MainFacilityTarget') ?? [])].map((r) => ({
-                                                            ...r,
-                                                            __checked: checked ? 'Y' : '',
-                                                        }));
-                                                        next.set('MainFacilityTarget', rows);
+                                                        const rows = [...(next.get('MainFacilityTarget') ?? [])];
+                                                        if (
+                                                            checked &&
+                                                            hasCheckedSelfMapping(rows, selectedMainFacilitySn)
+                                                        ) {
+                                                            next.set(
+                                                                'MainFacilityTarget',
+                                                                applyExclusiveSelfMappingChecks(
+                                                                    rows,
+                                                                    selectedMainFacilitySn,
+                                                                ),
+                                                            );
+                                                            return next;
+                                                        }
+                                                        next.set(
+                                                            'MainFacilityTarget',
+                                                            rows.map((r) => ({
+                                                                ...r,
+                                                                __checked:
+                                                                    checked &&
+                                                                    !isSelfMappingTarget(
+                                                                        r,
+                                                                        selectedMainFacilitySn,
+                                                                    )
+                                                                        ? 'Y'
+                                                                        : '',
+                                                            })),
+                                                        );
                                                         return next;
                                                     });
                                                 }
                                                 : undefined
                                         }
+                                        rightCheckableCallback={
+                                            tab.tabKey === 'ST00060002'
+                                                ? (row) => {
+                                                    const rows =
+                                                        rowDataMap.get('MainFacilityTarget') ?? [];
+                                                    if (
+                                                        !hasCheckedSelfMapping(
+                                                            rows,
+                                                            selectedMainFacilitySn,
+                                                        )
+                                                    ) {
+                                                        return true;
+                                                    }
+                                                    return isSelfMappingTarget(
+                                                        row,
+                                                        selectedMainFacilitySn,
+                                                    );
+                                                }
+                                                : undefined
+                                        }
                                         setLeftRowData={(updater) => {
                                             setRowDataMap((prev) => {
                                                 const next = new Map(prev);
diff --git a/apps/st/src/components/type/DataGrid.type.ts b/apps/st/src/components/type/DataGrid.type.ts
index 8f286df05..19c233180 100644
--- a/apps/st/src/components/type/DataGrid.type.ts
+++ b/apps/st/src/components/type/DataGrid.type.ts
@@ -418,6 +418,11 @@ export type DataGridProps = {
     onRowsChange?: (rows: Record<string, string | number>[]) => void;
     fixedColumns?: number; // 고정할 컬럼 개수 (좌측부터)
     showHeaderCheckbox?: boolean; // 헤더 체크박스 표시 여부 (기본값: true)
+    /** CheckBar 행별 체크 가능 여부 (false면 해당 행 체크박스 비활성) */
+    checkableCallback?: (
+        row: Record<string, string | number>,
+        itemIndex: number,
+    ) => boolean;
     rowData: Record<string, string | number>[];
     setRowData: React.Dispatch<
         React.SetStateAction<Record<string, string | number>[]>
@@ -532,6 +537,11 @@ export type SplitDataGridProps = {
     rightOnItemChecked?: (itemIndex: number, checked: boolean) => void;
     /** 우측 분할 그리드 헤더 전체 체크 변경 */
     rightOnItemAllChecked?: (checked: boolean) => void;
+    /** 우측 분할 그리드 행별 체크 가능 여부 */
+    rightCheckableCallback?: (
+        row: Record<string, string | number>,
+        itemIndex: number,
+    ) => boolean;
     /** 전체 정렬 기능 on/off (기본값: false) */
     enableSort?: boolean;
 };
diff --git a/apps/st/src/components/util/column/input/PublicSewageFactInpColumn/MainFacilityInpColumn.ts b/apps/st/src/components/util/column/input/PublicSewageFactInpColumn/MainFacilityInpColumn.ts
index 14cb5281d..31c33a0fd 100644
--- a/apps/st/src/components/util/column/input/PublicSewageFactInpColumn/MainFacilityInpColumn.ts
+++ b/apps/st/src/components/util/column/input/PublicSewageFactInpColumn/MainFacilityInpColumn.ts
@@ -70,7 +70,7 @@ export const MainFacilityTargetColumn = {
 
 export const MainFacilityInpColumn = {
     tabKey: 'ST00060002',
-    tabLabel: '중심 처리 시설',
+    tabLabel: '위탁 관리 입력',
     isSplitGrid: true,
     left: MainFacilityColumn,
     right: MainFacilityTargetColumn,
diff --git a/apps/st/src/components/util/grid/computedFieldCallbacks.ts b/apps/st/src/components/util/grid/computedFieldCallbacks.ts
index 245974fc9..b38d546ee 100644
--- a/apps/st/src/components/util/grid/computedFieldCallbacks.ts
+++ b/apps/st/src/components/util/grid/computedFieldCallbacks.ts
@@ -1,4 +1,13 @@
-import type { ComputedFieldConfig,DataFieldValueCallback } from "@/components/type/DataGrid.type";
+import Decimal from "decimal.js";
+
+import type { ComputedFieldConfig, DataFieldValueCallback } from "@/components/type/DataGrid.type";
+
+import {
+    decimalToGridNumber,
+    sumDecimals,
+    toDecimal,
+    truncDecimal,
+} from "@/components/util/grid/decimalNumber";
 
 /** 값 → 숫자 변환 (null/undefined/빈문자열 → 0) */
 function toNum(v: unknown): number {
@@ -8,78 +17,41 @@ function toNum(v: unknown): number {
     return isNaN(n) ? 0 : n;
 }
 
-/** 소수점 첫째 자리 이후 버림 (반올림 없음) */
-function truncateToFirstDecimal(value: number): number {
-    if (!Number.isFinite(value)) return 0;
-    return Math.floor(value * 10) / 10;
-}
-
-/** computed sum용 스케일 (표시 최대 소수 3자리 + 여유) */
-const SUM_DECIMAL_SCALE = 1e6;
-
-/**
- * 스케일 정수 합을 Number로 되돌릴 때 생기는 IEEE 오차 보정.
- * 39057.34는 이진수로 39057.33999… 가 되어 RealGrid `#,##0.00` 절사 시 39057.33이 된다.
- * 1e-12는 이 값에서 *100 경계를 넘지 못하므로, 값 크기에 비례한 ULP만큼 밀어 올린다.
- */
-function numberFromScaledSum(scaledSum: number): number {
-    if (scaledSum === 0) return 0;
-    const raw = scaledSum / SUM_DECIMAL_SCALE;
-    const ulp = Number.EPSILON * Math.max(1, Math.abs(raw));
-    return raw + Math.sign(raw) * ulp * 8;
-}
-
-/**
- * 각 값을 소수 6자리 정수로 올린 뒤 더한 다음 다시 나눈다.
- * 예: 2712.5 + 6291.13 → (2712500000 + 6291130000) / 1e6 = 9003.63
- */
-function sumViaScaledIntegers(nums: number[]): number {
-    let scaledSum = 0;
-    for (const n of nums) {
-        if (!Number.isFinite(n)) continue;
-        scaledSum += Math.round(n * SUM_DECIMAL_SCALE);
-    }
-    return numberFromScaledSum(scaledSum);
-}
-
-/** 합계용 valueCallback 생성 */
-export function createSumValueCallback(fieldNames: string[]): DataFieldValueCallback {
-    return (_prod, _dataRow, _fieldName, fieldNamesArr, values) => {
-        const nums: number[] = [];
-        for (const f of fieldNames) {
-            const idx = fieldNamesArr.indexOf(f);
-            if (idx >= 0) nums.push(toNum(values[idx]));
-        }
-        return sumViaScaledIntegers(nums);
-    };
-}
-
-/** 평균용 valueCallback 생성 */
-export function createAvgValueCallback(fieldNames: string[]): DataFieldValueCallback {
-    return (_prod, _dataRow, _fieldName, fieldNamesArr, values) => {
-        const nums: number[] = [];
-        for (const f of fieldNames) {
-            const idx = fieldNamesArr.indexOf(f);
-            if (idx >= 0) {
-                nums.push(toNum(values[idx]));
-            }
-        }
-        if (nums.length === 0) return 0;
-        return sumViaScaledIntegers(nums) / nums.length;
-    };
-}
-
-function sumFieldValues(
+function fieldNums(
     fields: string[],
     fieldNamesArr: string[],
     values: unknown[],
-): number {
+): number[] {
     const nums: number[] = [];
     for (const f of fields) {
         const idx = fieldNamesArr.indexOf(f);
         if (idx >= 0) nums.push(toNum(values[idx]));
     }
-    return sumViaScaledIntegers(nums);
+    return nums;
+}
+
+function fieldDecimal(
+    field: string,
+    fieldNamesArr: string[],
+    values: unknown[],
+): Decimal {
+    const idx = fieldNamesArr.indexOf(field);
+    return toDecimal(idx >= 0 ? toNum(values[idx]) : 0);
+}
+
+/** 합계용 valueCallback 생성 */
+export function createSumValueCallback(fieldNames: string[]): DataFieldValueCallback {
+    return (_prod, _dataRow, _fieldName, fieldNamesArr, values) =>
+        decimalToGridNumber(sumDecimals(fieldNums(fieldNames, fieldNamesArr, values)));
+}
+
+/** 평균용 valueCallback 생성 */
+export function createAvgValueCallback(fieldNames: string[]): DataFieldValueCallback {
+    return (_prod, _dataRow, _fieldName, fieldNamesArr, values) => {
+        const nums = fieldNums(fieldNames, fieldNamesArr, values);
+        if (nums.length === 0) return 0;
+        return decimalToGridNumber(sumDecimals(nums).div(nums.length));
+    };
 }
 
 /** halfSumOfSums 한 건 — (sum(first) + sum(second)) / 2, 소수 내림 */
@@ -89,9 +61,9 @@ function computeHalfSumOfSums(
     fieldNamesArr: string[],
     values: unknown[],
 ): number {
-    const firstSum = sumFieldValues(firstSumFields, fieldNamesArr, values);
-    const secondSum = sumFieldValues(secondSumFields, fieldNamesArr, values);
-    return Math.floor((firstSum + secondSum) / 2);
+    const firstSum = sumDecimals(fieldNums(firstSumFields, fieldNamesArr, values));
+    const secondSum = sumDecimals(fieldNums(secondSumFields, fieldNamesArr, values));
+    return firstSum.plus(secondSum).div(2).floor().toNumber();
 }
 
 export type HalfSumOfSumsGroup = {
@@ -134,11 +106,9 @@ export function createDifferenceValueCallback(fields: string[]): DataFieldValueC
     const b = fields[1] ?? "";
     return (_prod, _dataRow, _fieldName, fieldNamesArr, values) => {
         if (!a || !b) return 0;
-        const ia = fieldNamesArr.indexOf(a);
-        const ib = fieldNamesArr.indexOf(b);
-        const va = ia >= 0 ? toNum(values[ia]) : 0;
-        const vb = ib >= 0 ? toNum(values[ib]) : 0;
-        return va - vb;
+        return decimalToGridNumber(
+            fieldDecimal(a, fieldNamesArr, values).minus(fieldDecimal(b, fieldNamesArr, values)),
+        );
     };
 }
 
@@ -148,15 +118,9 @@ export function createDifferenceOfSumsValueCallback(
     subtrahendFields: string[],
 ): DataFieldValueCallback {
     return (_prod, _dataRow, _fieldName, fieldNamesArr, values) => {
-        const sumOf = (fields: string[]) => {
-            let sum = 0;
-            for (const f of fields) {
-                const idx = fieldNamesArr.indexOf(f);
-                if (idx >= 0) sum += toNum(values[idx]);
-            }
-            return sum;
-        };
-        return sumOf(minuendFields) - sumOf(subtrahendFields);
+        const minuend = sumDecimals(fieldNums(minuendFields, fieldNamesArr, values));
+        const subtrahend = sumDecimals(fieldNums(subtrahendFields, fieldNamesArr, values));
+        return decimalToGridNumber(minuend.minus(subtrahend));
     };
 }
 
@@ -181,14 +145,9 @@ export function createMaxOfFieldAndSumValueCallback(
     sumFields: string[],
 ): DataFieldValueCallback {
     return (_prod, _dataRow, _fieldName, fieldNamesArr, values) => {
-        const baseIdx = fieldNamesArr.indexOf(baseField);
-        const baseVal = baseIdx >= 0 ? toNum(values[baseIdx]) : 0;
-        let sumVal = 0;
-        for (const f of sumFields) {
-            const idx = fieldNamesArr.indexOf(f);
-            if (idx >= 0) sumVal += toNum(values[idx]);
-        }
-        return Math.max(baseVal, sumVal);
+        const baseVal = fieldDecimal(baseField, fieldNamesArr, values);
+        const sumVal = sumDecimals(fieldNums(sumFields, fieldNamesArr, values));
+        return decimalToGridNumber(Decimal.max(baseVal, sumVal));
     };
 }
 
@@ -197,18 +156,13 @@ export function createSumOfMaxOfFieldAndSumGroupsValueCallback(
     groups: Array<{ baseField: string; sumFields: string[] }>,
 ): DataFieldValueCallback {
     return (_prod, _dataRow, _fieldName, fieldNamesArr, values) => {
-        let total = 0;
+        let total = new Decimal(0);
         for (const group of groups) {
-            const baseIdx = fieldNamesArr.indexOf(group.baseField);
-            const baseVal = baseIdx >= 0 ? toNum(values[baseIdx]) : 0;
-            let sumVal = 0;
-            for (const f of group.sumFields) {
-                const idx = fieldNamesArr.indexOf(f);
-                if (idx >= 0) sumVal += toNum(values[idx]);
-            }
-            total += Math.max(baseVal, sumVal);
+            const baseVal = fieldDecimal(group.baseField, fieldNamesArr, values);
+            const sumVal = sumDecimals(fieldNums(group.sumFields, fieldNamesArr, values));
+            total = total.plus(Decimal.max(baseVal, sumVal));
         }
-        return total;
+        return decimalToGridNumber(total);
     };
 }
 
@@ -218,17 +172,10 @@ export function createCoverageRateValueCallback(
     denominatorFields: string[]
 ): DataFieldValueCallback {
     return (_prod, _dataRow, _fieldName, fieldNamesArr, values) => {
-        const getSum = (fields: string[]) => {
-            let sum = 0;
-            for (const f of fields) {
-                const idx = fieldNamesArr.indexOf(f);
-                if (idx >= 0) sum += toNum(values[idx]);
-            }
-            return sum;
-        };
-        const total2 = getSum(numeratorFields);
-        const total1 = getSum(denominatorFields);
-        return total1 === 0 ? 0 : (total2 / total1) * 100;
+        const total2 = sumDecimals(fieldNums(numeratorFields, fieldNamesArr, values));
+        const total1 = sumDecimals(fieldNums(denominatorFields, fieldNamesArr, values));
+        if (total1.isZero()) return 0;
+        return decimalToGridNumber(total2.div(total1).times(100));
     };
 }
 
@@ -239,28 +186,27 @@ export function createSwrgInstlrtRateValueCallback(
     thirdFields: string[],
 ): DataFieldValueCallback {
     return (_prod, _dataRow, _fieldName, fieldNamesArr, values) => {
+        const trunc1 = (d: Decimal) => truncDecimal(d, 1);
         const getSum = (fields: string[]) => {
-            let sum = 0;
+            let sum = new Decimal(0);
             for (const f of fields) {
                 const idx = fieldNamesArr.indexOf(f);
                 if (idx >= 0) {
-                    sum += truncateToFirstDecimal(toNum(values[idx]));
+                    sum = sum.plus(trunc1(toDecimal(toNum(values[idx]))));
                 }
             }
-            return truncateToFirstDecimal(sum);
+            return trunc1(sum);
         };
         const sum1 = getSum(numeratorFields);
         const sum2 = getSum(denominatorFields);
+        const piplSupprt = trunc1(fieldDecimal(thirdFields[0] || "piplSupprt", fieldNamesArr, values));
 
-        const piplSupprt = truncateToFirstDecimal(
-            toNum(values[fieldNamesArr.indexOf(thirdFields[0] || "piplSupprt")]),
-        );
+        const ratioPercent = sum1.isZero()
+            ? new Decimal(0)
+            : trunc1(sum2.div(sum1).times(100));
+        const result = trunc1(ratioPercent.times(piplSupprt).div(100));
 
-        const ratioPercent =
-            sum1 === 0 ? 0 : truncateToFirstDecimal((sum2 / sum1) * 100);
-        const result = truncateToFirstDecimal((ratioPercent * piplSupprt) / 100);
-
-        return result;
+        return decimalToGridNumber(result);
     };
 }
 
@@ -270,12 +216,10 @@ export function createBodPrcsRtValueCallback(
     dschgField: string,
 ): DataFieldValueCallback {
     return (_prod, _dataRow, _fieldName, fieldNamesArr, values) => {
-        const inflwIdx = fieldNamesArr.indexOf(inflwField);
-        const dschgIdx = fieldNamesArr.indexOf(dschgField);
-        const inflw = inflwIdx >= 0 ? toNum(values[inflwIdx]) : 0;
-        const dschg = dschgIdx >= 0 ? toNum(values[dschgIdx]) : 0;
-        if (inflw === 0) return 0;
-        return (inflw - dschg) / inflw;
+        const inflw = fieldDecimal(inflwField, fieldNamesArr, values);
+        const dschg = fieldDecimal(dschgField, fieldNamesArr, values);
+        if (inflw.isZero()) return 0;
+        return decimalToGridNumber(inflw.minus(dschg).div(inflw));
     };
 }
 
@@ -288,17 +232,14 @@ export function createPumpGrossPpqtyValueCallback(
     }>,
 ): DataFieldValueCallback {
     return (_prod, _dataRow, _fieldName, fieldNamesArr, values) => {
-        let total = 0;
+        let total = new Decimal(0);
         for (const group of pumpGroups) {
-            const pumpIdx = fieldNamesArr.indexOf(group.pumpCntField);
-            const rsrvIdx = fieldNamesArr.indexOf(group.rsrvPumpCntField);
-            const perIdx = fieldNamesArr.indexOf(group.perPpqtyField);
-            const pumpCnt = pumpIdx >= 0 ? toNum(values[pumpIdx]) : 0;
-            const rsrvCnt = rsrvIdx >= 0 ? toNum(values[rsrvIdx]) : 0;
-            const perPpqty = perIdx >= 0 ? toNum(values[perIdx]) : 0;
-            total += (pumpCnt + rsrvCnt) * perPpqty;
+            const pumpCnt = fieldDecimal(group.pumpCntField, fieldNamesArr, values);
+            const rsrvCnt = fieldDecimal(group.rsrvPumpCntField, fieldNamesArr, values);
+            const perPpqty = fieldDecimal(group.perPpqtyField, fieldNamesArr, values);
+            total = total.plus(pumpCnt.plus(rsrvCnt).times(perPpqty));
         }
-        return total;
+        return decimalToGridNumber(total);
     };
 }
 
@@ -310,18 +251,14 @@ export function createQuotientRatioPercentValueCallback(
     const [numField, numDenField] = numeratorQuotient;
     const [denNumField, denDenField] = denominatorQuotient;
     return (_prod, _dataRow, _fieldName, fieldNamesArr, values) => {
-        const getVal = (field: string) => {
-            const idx = fieldNamesArr.indexOf(field);
-            return idx >= 0 ? toNum(values[idx]) : 0;
-        };
-        const numDen = getVal(numDenField);
-        const denDen = getVal(denDenField);
-        const denNum = getVal(denNumField);
-        if (numDen === 0 || denDen === 0 || denNum === 0) return 0;
-        const numerator = getVal(numField) / numDen;
-        const denominator = denNum / denDen;
-        if (denominator === 0) return 0;
-        return (numerator / denominator) * 100;
+        const numDen = fieldDecimal(numDenField, fieldNamesArr, values);
+        const denDen = fieldDecimal(denDenField, fieldNamesArr, values);
+        const denNum = fieldDecimal(denNumField, fieldNamesArr, values);
+        if (numDen.isZero() || denDen.isZero() || denNum.isZero()) return 0;
+        const numerator = fieldDecimal(numField, fieldNamesArr, values).div(numDen);
+        const denominator = denNum.div(denDen);
+        if (denominator.isZero()) return 0;
+        return decimalToGridNumber(numerator.div(denominator).times(100));
     };
 }
 
@@ -331,11 +268,10 @@ export function createSumPerTenThousandValueCallback(
     denominatorField: string,
 ): DataFieldValueCallback {
     return (_prod, _dataRow, _fieldName, fieldNamesArr, values) => {
-        const sum = sumFieldValues(numeratorFields, fieldNamesArr, values);
-        const denIdx = fieldNamesArr.indexOf(denominatorField);
-        const den = denIdx >= 0 ? toNum(values[denIdx]) : 0;
-        if (den === 0) return 0;
-        return truncateToFirstDecimal((sum / den) * 10000);
+        const den = fieldDecimal(denominatorField, fieldNamesArr, values);
+        if (den.isZero()) return 0;
+        const sum = sumDecimals(fieldNums(numeratorFields, fieldNamesArr, values));
+        return decimalToGridNumber(truncDecimal(sum.div(den).times(10000), 1));
     };
 }
 
@@ -345,12 +281,11 @@ export function createQuotientValueCallback(fields: string[]): DataFieldValueCal
     const denominatorField = fields[1] ?? "";
     return (_prod, _dataRow, _fieldName, fieldNamesArr, values) => {
         if (!numeratorField || !denominatorField) return 0;
-        const numIdx = fieldNamesArr.indexOf(numeratorField);
-        const denIdx = fieldNamesArr.indexOf(denominatorField);
-        const numerator = numIdx >= 0 ? toNum(values[numIdx]) : 0;
-        const denominator = denIdx >= 0 ? toNum(values[denIdx]) : 0;
-        if (denominator === 0) return 0;
-        return numerator / denominator;
+        const denominator = fieldDecimal(denominatorField, fieldNamesArr, values);
+        if (denominator.isZero()) return 0;
+        return decimalToGridNumber(
+            fieldDecimal(numeratorField, fieldNamesArr, values).div(denominator),
+        );
     };
 }
 
@@ -361,15 +296,11 @@ export function createQuotientTimesMultiplierPercentValueCallback(
     multiplierField: string,
 ): DataFieldValueCallback {
     return (_prod, _dataRow, _fieldName, fieldNamesArr, values) => {
-        const getVal = (field: string) => {
-            const idx = fieldNamesArr.indexOf(field);
-            return idx >= 0 ? toNum(values[idx]) : 0;
-        };
-        const denominator = getVal(denominatorField);
-        if (denominator === 0) return 0;
-        const quotient = getVal(numeratorField) / denominator;
-        const multiplier = getVal(multiplierField);
-        return truncateToFirstDecimal(quotient * multiplier * 100);
+        const denominator = fieldDecimal(denominatorField, fieldNamesArr, values);
+        if (denominator.isZero()) return 0;
+        const quotient = fieldDecimal(numeratorField, fieldNamesArr, values).div(denominator);
+        const multiplier = fieldDecimal(multiplierField, fieldNamesArr, values);
+        return decimalToGridNumber(truncDecimal(quotient.times(multiplier).times(100), 1));
     };
 }
 
diff --git a/apps/st/src/components/util/grid/decimalNumber.ts b/apps/st/src/components/util/grid/decimalNumber.ts
new file mode 100644
index 000000000..5034dfb7c
--- /dev/null
+++ b/apps/st/src/components/util/grid/decimalNumber.ts
@@ -0,0 +1,100 @@
+import Decimal from "decimal.js";
+
+import type { DataFieldValueCallback } from "@/components/type/DataGrid.type";
+
+/** IEEE Number를 최단 십진 문자열로 복원 (69.96 → "69.96") */
+export function toDecimal(n: number): Decimal {
+    if (!Number.isFinite(n) || n === 0) return new Decimal(0);
+    return new Decimal(n.toString());
+}
+
+function ulpOf(n: number): number {
+    return Number.EPSILON * Math.max(1, Math.abs(n));
+}
+
+/** RealGrid `#,##0.0` / `.00` / `.000` 절사가 의도한 십진값보다 작아지는지 */
+function needsDisplayNudge(n: number, intended: Decimal): boolean {
+    for (const places of [1, 2, 3] as const) {
+        const factor = 10 ** places;
+        const scaled = n * factor;
+        const ieeeTrunc = n >= 0 ? Math.floor(scaled) : Math.ceil(scaled);
+        const intendedTrunc = intended.times(new Decimal(10).pow(places)).trunc();
+        if (n >= 0 && new Decimal(ieeeTrunc).lt(intendedTrunc)) return true;
+        if (n < 0 && new Decimal(ieeeTrunc).gt(intendedTrunc)) return true;
+    }
+    return false;
+}
+
+/**
+ * Decimal → RealGrid Number.
+ * 18856.1처럼 이진 근사가 실제보다 작으면 `#,##0.00` 절사 시 18856.09가 되므로
+ * 그때만 1 ULP씩 올려 표시를 맞춘다. 14384.26처럼 이미 충분한 값은 그대로 둔다.
+ */
+export function decimalToGridNumber(value: Decimal): number {
+    if (value.isZero()) return 0;
+    let n = value.toNumber();
+    const sign = Math.sign(n) || 1;
+    for (let i = 0; i < 16; i++) {
+        if (!needsDisplayNudge(n, value)) return n;
+        n += sign * ulpOf(n);
+    }
+    return n;
+}
+
+export function truncDecimal(value: Decimal, decimalPlaces: number): Decimal {
+    if (decimalPlaces < 0) return value;
+    const factor = new Decimal(10).pow(decimalPlaces);
+    return value.times(factor).trunc().div(factor);
+}
+
+/**
+ * 절삭. `18856.1 * 100`이 1885609.999…가 되어 Math.floor 시 18856.09가 되므로
+ * 최단 십진 문자열로 복원한 뒤 Decimal trunc, RealGrid 표시용으로 ULP 보정.
+ */
+export function truncateByDecimalPlaces(value: number, decimalPlaces: number): number {
+    if (!Number.isFinite(value)) return 0;
+    if (decimalPlaces < 0) return value;
+    return decimalToGridNumber(truncDecimal(toDecimal(value), decimalPlaces));
+}
+
+export function getDecimalPlacesFromDataFormat(dataFormat?: string): number | null {
+    if (!dataFormat) return null;
+    const match = dataFormat.match(/\.(0+|#+)/);
+    const decimalToken = match?.[1];
+    if (decimalToken) return decimalToken.length;
+    if (/[#0]/.test(dataFormat)) return 0;
+    return null;
+}
+
+export function wrapWithFormatTruncate(
+    callback: DataFieldValueCallback,
+    dataFormat?: string,
+): (
+    prod: unknown,
+    dataRow: number,
+    fieldName: string,
+    fieldNames: string[],
+    values: unknown[],
+) => number {
+    const decimalPlaces = getDecimalPlacesFromDataFormat(dataFormat);
+    return (prod, dataRow, fieldName, fieldNames, values) => {
+        const computedValue = callback(prod, dataRow, fieldName, fieldNames, values);
+        const n = typeof computedValue === "number" ? computedValue : Number(computedValue);
+        const num = Number.isFinite(n) ? n : 0;
+        if (decimalPlaces == null) return num;
+        return truncateByDecimalPlaces(num, decimalPlaces);
+    };
+}
+
+export function sumDecimals(nums: number[]): Decimal {
+    let sum = new Decimal(0);
+    for (const n of nums) {
+        if (!Number.isFinite(n)) continue;
+        sum = sum.plus(toDecimal(n));
+    }
+    return sum;
+}
+
+export function sumToGridNumber(nums: number[]): number {
+    return decimalToGridNumber(sumDecimals(nums));
+}
diff --git a/apps/st/src/components/util/grid/footerSummary.ts b/apps/st/src/components/util/grid/footerSummary.ts
index ba709d4d4..225a0a63d 100644
--- a/apps/st/src/components/util/grid/footerSummary.ts
+++ b/apps/st/src/components/util/grid/footerSummary.ts
@@ -1,52 +1,51 @@
-import type { DataColumn,GridView } from "@/components/type/DataGrid.type";
+import type { DataColumn, GridView } from "@/components/type/DataGrid.type";
 
-// 그리드 푸터 합계 계산 함수 (계산 로직)
-export const getFooterSummary = (grid: GridView, column: DataColumn) => {
-    // 데이터 소스에서 직접 합계 계산
+import {
+    decimalToGridNumber,
+    sumDecimals,
+    truncDecimal,
+} from "@/components/util/grid/decimalNumber";
+
+function toNumeric(cellValue: unknown): number | null {
+    if (cellValue == null || cellValue === "") return null;
+    const numericValue =
+        typeof cellValue === "string"
+            ? Number(String(cellValue).replace(/,/g, ""))
+            : Number(cellValue);
+    if (!Number.isFinite(numericValue)) return null;
+    return numericValue;
+}
+
+function collectNumericValues(
+    grid: GridView,
+    column: DataColumn,
+    includeRow?: (rowIndex: number) => boolean,
+): number[] {
     const dataSource = grid.getDataSource();
     const rowCount = dataSource.getRowCount();
-    let sum = 0;
+    const nums: number[] = [];
 
     for (let i = 0; i < rowCount; i++) {
-        const cellValue = dataSource.getValue(i, column.fieldName);
-        
-        // 문자열인 경우 숫자로 변환
-        const numericValue = typeof cellValue === 'string'
-            ? Number(String(cellValue).replace(/,/g, ''))
-            : Number(cellValue);
-
-        if (!isNaN(numericValue) && numericValue !== null && numericValue !== undefined) {
-            sum += numericValue;
-        }
+        if (includeRow && !includeRow(i)) continue;
+        const n = toNumeric(dataSource.getValue(i, column.fieldName));
+        if (n != null) nums.push(n);
     }
 
-    return sum;
-};
+    return nums;
+}
+
+// 그리드 푸터 합계 계산 함수 (계산 로직)
+export const getFooterSummary = (grid: GridView, column: DataColumn) =>
+    decimalToGridNumber(sumDecimals(collectNumericValues(grid, column)));
 
 // 평균 계산 함수
 export const getFooterAvgSummary = (grid: GridView, column: DataColumn) => {
-    const dataSource = grid.getDataSource();
-    const rowCount = dataSource.getRowCount();
-
-    let sum = 0;
-    let avg = 0;
-
-    for (let i = 0; i < rowCount; i++) {
-        const cellValue = dataSource.getValue(i, column.fieldName);
-        
-        const numericValue = typeof cellValue === 'string'
-            ? Number(String(cellValue).replace(/,/g, ''))
-            : Number(cellValue);
-
-        if (!isNaN(numericValue) && numericValue !== null && numericValue !== undefined) {
-            sum += numericValue;
-        }
-    }
-
-    avg = sum / rowCount;
-
-    return Math.floor(avg * 10) / 10;
-}
+    const nums = collectNumericValues(grid, column);
+    const rowCount = grid.getDataSource().getRowCount();
+    if (rowCount === 0) return 0;
+    const avg = sumDecimals(nums).div(rowCount);
+    return decimalToGridNumber(truncDecimal(avg, 1));
+};
 
 // 구분 필드의 고유값들을 찾는 함수 (첫 번째, 두 번째). 기본 필드명 'displayYear'
 const getDivisionValues = (grid: GridView, divisionFieldName: string = 'displayYear'): string[] => {
@@ -73,38 +72,21 @@ export const getFooterSummaryByDivision = (
     divisionIndex: number,
     divisionFieldName: string = 'displayYear'
 ) => {
-    const dataSource = grid.getDataSource();
-    const rowCount = dataSource.getRowCount();
-    let sum = 0;
-
-    // "구분" 필드의 고유값 찾기
     const divisionValues = getDivisionValues(grid, divisionFieldName);
     if (divisionValues.length <= divisionIndex) {
-        return 0; // 해당 인덱스의 고유값이 없으면 0 반환
+        return 0;
     }
     
     const targetDivision = divisionValues[divisionIndex];
+    const dataSource = grid.getDataSource();
 
-    for (let i = 0; i < rowCount; i++) {
-        // "구분" 필드 값 확인
-        const divisionValue = dataSource.getValue(i, divisionFieldName);
-        if (String(divisionValue) !== targetDivision) {
-            continue; // 해당 "구분" 값이 아니면 스킵
-        }
-
-        const cellValue = dataSource.getValue(i, column.fieldName);
-        
-        // 문자열인 경우 숫자로 변환
-        const numericValue = typeof cellValue === 'string'
-            ? Number(String(cellValue).replace(/,/g, ''))
-            : Number(cellValue);
-
-        if (!isNaN(numericValue) && numericValue !== null && numericValue !== undefined) {
-            sum += numericValue;
-        }
-    }
-
-    return sum;
+    return decimalToGridNumber(
+        sumDecimals(
+            collectNumericValues(grid, column, (i) =>
+                String(dataSource.getValue(i, divisionFieldName)) === targetDivision,
+            ),
+        ),
+    );
 };
 
 // 구분 필드 값에 따라 필터링하여 평균 계산하는 함수. 기본 필드명 'displayYear'
@@ -115,45 +97,22 @@ export const getFooterAvgSummaryByDivision = (
     divisionIndex: number,
     divisionFieldName: string = 'displayYear'
 ) => {
-    const dataSource = grid.getDataSource();
-    const rowCount = dataSource.getRowCount();
-    let sum = 0;
-    let count = 0;
-
-    // "구분" 필드의 고유값 찾기
     const divisionValues = getDivisionValues(grid, divisionFieldName);
     if (divisionValues.length <= divisionIndex) {
-        return 0; // 해당 인덱스의 고유값이 없으면 0 반환
+        return 0;
     }
     
     const targetDivision = divisionValues[divisionIndex];
+    const dataSource = grid.getDataSource();
+    const nums = collectNumericValues(grid, column, (i) =>
+        String(dataSource.getValue(i, divisionFieldName)) === targetDivision,
+    );
 
-    for (let i = 0; i < rowCount; i++) {
-        // "구분" 필드 값 확인
-        const divisionValue = dataSource.getValue(i, divisionFieldName);
-        if (String(divisionValue) !== targetDivision) {
-            continue; // 해당 "구분" 값이 아니면 스킵
-        }
-
-        const cellValue = dataSource.getValue(i, column.fieldName);
-        
-        // 문자열인 경우 숫자로 변환
-        const numericValue = typeof cellValue === 'string'
-            ? Number(String(cellValue).replace(/,/g, ''))
-            : Number(cellValue);
-
-        if (!isNaN(numericValue) && numericValue !== null && numericValue !== undefined) {
-            sum += numericValue;
-            count += 1;
-        }
-    }
-
-    if (count === 0) {
+    if (nums.length === 0) {
         return 0;
     }
 
-    const avg = sum / count;
-    return Math.floor(avg * 10) / 10;
+    return decimalToGridNumber(truncDecimal(sumDecimals(nums).div(nums.length), 1));
 };
 
 // Footer 설정 객체 생성 함수
@@ -249,4 +208,4 @@ export const footerDecimal3ArrayByDivision = createSumFooterArrayByDivision('#,#
 export const footerAvgDecimal = createAvgFooter('#,##0.0');
 
 // "구분" 값에 따라 필터링하는 평균 Footer 배열 (소수점 1자리, 2줄)
-export const footerAvgDecimalArrayByDivision = createAvgFooterArrayByDivision('#,##0.0');
\ No newline at end of file
+export const footerAvgDecimalArrayByDivision = createAvgFooterArrayByDivision('#,##0.0');