diff --git a/front/src/modules/timesStops/DurationCell.tsx b/front/src/modules/timesStops/DurationCell.tsx
index c3397ba1c61..a02748d383a 100644
--- a/front/src/modules/timesStops/DurationCell.tsx
+++ b/front/src/modules/timesStops/DurationCell.tsx
@@ -395,18 +395,15 @@ export type DurationCellHandle = {
   focus: () => void;
 };
 
-const DurationCell = ({
-  disabled,
-  clearButtonTitle,
-  ref,
-  ...props
-}: CellContext<TimesStopsRowNew, Duration | null> &
+type DurationCellProps = CellContext<TimesStopsRowNew, Duration | null> &
   Omit<React.HTMLAttributes<HTMLDivElement>, 'onChange'> & {
-    onCommit?: (seconds: number | null, propagationMode: StopPropagationMode) => void;
+    onCommit?: (value: Duration | null, propagationMode: StopPropagationMode) => void;
     disabled?: boolean;
     clearButtonTitle?: string;
     ref?: React.Ref<DurationCellHandle>;
-  }) => {
+  };
+
+const DurationCell = ({ disabled, clearButtonTitle, ref, ...props }: DurationCellProps) => {
   const { onCommit, getValue, row, table } = props || {};
   const controlledValue = getValue();
   const [state, dispatch] = useReducer(durationReducer, controlledValue, initialDurationState);
@@ -458,7 +455,8 @@ const DurationCell = ({
       const newSeconds = unitsToSeconds(state.units);
       const initialSeconds =
         controlledValue !== null ? Math.round(controlledValue.total('second')) : null;
-      if (newSeconds !== initialSeconds) onCommit?.(newSeconds, propagationMode);
+      const newValue = new Duration({ seconds: newSeconds });
+      if (newSeconds !== initialSeconds) onCommit?.(newValue, propagationMode);
     }
     dispatch({ type: 'STOP_EDITING' });
   };
diff --git a/front/src/modules/timesStops/TimeStopsTableWrapper.tsx b/front/src/modules/timesStops/TimeStopsTableWrapper.tsx
index 515f67c0965..167f995899b 100644
--- a/front/src/modules/timesStops/TimeStopsTableWrapper.tsx
+++ b/front/src/modules/timesStops/TimeStopsTableWrapper.tsx
@@ -259,7 +259,7 @@ const TimeStopsTableWrapper = ({
           rowId: singleEdit.rowId,
           field: 'stopDurationWithArrival',
           value: {
-            stop: update.value !== null ? new Duration({ seconds: update.value }) : null,
+            stop: update.value,
             arrival: editedRowArrivalEdit.value ?? propagationResult.updatedStartTime,
           },
         }
@@ -336,22 +336,22 @@ const TimeStopsTableWrapper = ({
 
   const handleStopDurationChange = (
     row: TimesStopsRowNew,
-    durationSeconds: number | null,
+    duration: Duration | null,
     propagationMode: StopPropagationMode
   ) => {
     const singleEdit: PendingEdit = {
       rowId: row.id,
       field: 'stopDuration',
-      value: durationSeconds !== null ? new Duration({ seconds: durationSeconds }) : null,
+      value: duration,
     };
     commitEdit(
       buildEditsForStopDurationUpdate(singleEdit, {
         row,
         field: 'stopDuration',
-        value: durationSeconds,
+        value: duration,
         propagationMode,
       }),
-      () => updateStopDuration(row, durationSeconds, propagationMode)
+      () => updateStopDuration(row, duration, propagationMode)
     );
   };
 
diff --git a/front/src/modules/timesStops/TimesStopsTable.tsx b/front/src/modules/timesStops/TimesStopsTable.tsx
index ac5dd208832..631d5e80327 100644
--- a/front/src/modules/timesStops/TimesStopsTable.tsx
+++ b/front/src/modules/timesStops/TimesStopsTable.tsx
@@ -51,7 +51,7 @@ declare module '@tanstack/react-table' {
     ) => void;
     onStopDurationChange: (
       row: TimesStopsRowNew,
-      durationSeconds: number | null,
+      duration: Duration | null,
       propagationMode: StopPropagationMode
     ) => void;
     onDepartureChange: (
@@ -113,7 +113,7 @@ type TimesStopsTableProps = {
   ) => void;
   onStopDurationChange: (
     row: TimesStopsRowNew,
-    durationSeconds: number | null,
+    duration: Duration | null,
     propagationMode: StopPropagationMode
   ) => void;
   onDepartureChange: (
diff --git a/front/src/modules/timesStops/helpers/__tests__/stopDurationPropagation.spec.ts b/front/src/modules/timesStops/helpers/__tests__/stopDurationPropagation.spec.ts
index a10a93cbac6..6939aa38b92 100644
--- a/front/src/modules/timesStops/helpers/__tests__/stopDurationPropagation.spec.ts
+++ b/front/src/modules/timesStops/helpers/__tests__/stopDurationPropagation.spec.ts
@@ -59,7 +59,7 @@ describe('propagateStopDuration', () => {
         {
           row: makeRow('PT5M'),
           field: 'stopDuration',
-          value: 900,
+          value: new Duration({ minutes: 15 }),
           propagationMode: 'atThisWaypoint',
         },
         train
@@ -70,7 +70,7 @@ describe('propagateStopDuration', () => {
         {
           row: { ...makeRow('PT5M'), pathStepId: null },
           field: 'stopDuration',
-          value: 900,
+          value: new Duration({ minutes: 15 }),
           propagationMode: 'toDestination',
         },
         train
@@ -82,7 +82,12 @@ describe('propagateStopDuration', () => {
     const train = makeTrain('PT5M');
     const row = makeRow('PT5M');
     const result = propagateStopDuration(
-      { row, field: 'stopDuration', value: 900, propagationMode: 'toDestination' }, // +10min
+      {
+        row,
+        field: 'stopDuration',
+        value: new Duration({ minutes: 15 }),
+        propagationMode: 'toDestination',
+      }, // +10min
       train
     );
     expect(result).toBeDefined();
@@ -101,7 +106,12 @@ describe('propagateStopDuration', () => {
       const train = makeTrain('PT5M');
       const row = makeRow('PT5M');
       const result = propagateStopDuration(
-        { row, field: 'stopDuration', value: 600, propagationMode: 'fromDeparture' }, // +5min
+        {
+          row,
+          field: 'stopDuration',
+          value: new Duration({ minutes: 10 }),
+          propagationMode: 'fromDeparture',
+        }, // +5min
         train
       );
       expect(result).toBeDefined();
@@ -119,7 +129,12 @@ describe('propagateStopDuration', () => {
       const train = makeTrainWithoutOp11();
       const row = makeRow(null);
       const result = propagateStopDuration(
-        { row, field: 'stopDuration', value: 600, propagationMode: 'fromDeparture' }, // +10min
+        {
+          row,
+          field: 'stopDuration',
+          value: new Duration({ minutes: 10 }),
+          propagationMode: 'fromDeparture',
+        }, // +10min
         train
       );
       expect(result).toBeDefined();
diff --git a/front/src/modules/timesStops/helpers/stopDurationPropagation.ts b/front/src/modules/timesStops/helpers/stopDurationPropagation.ts
index 03a31392aaa..6f2c4ee5a1d 100644
--- a/front/src/modules/timesStops/helpers/stopDurationPropagation.ts
+++ b/front/src/modules/timesStops/helpers/stopDurationPropagation.ts
@@ -39,7 +39,7 @@ export const propagateStopDuration = (
 
   // Delta between the old and new stop duration — drives every shift below.
   const oldDuration = update.row.stopDuration ?? Duration.zero;
-  const newDuration = new Duration({ seconds: update.value });
+  const newDuration = update.value;
   const delta = newDuration.sub(oldDuration);
 
   // The edited point's current schedule state, if it already has one.
diff --git a/front/src/modules/timesStops/hooks/useUpdateTimesStopsTable.ts b/front/src/modules/timesStops/hooks/useUpdateTimesStopsTable.ts
index 01d4ba583cc..1f098c4c746 100644
--- a/front/src/modules/timesStops/hooks/useUpdateTimesStopsTable.ts
+++ b/front/src/modules/timesStops/hooks/useUpdateTimesStopsTable.ts
@@ -168,16 +168,7 @@ const useUpdateTimesStopsTable = (
         };
       }
 
-      // Convert CellUpdate to OptimisticEdit (stopDuration: number → Duration)
-      let edit: Exclude<OptimisticEdit, { field: 'powerRestriction' }>;
-      if (update.field === 'stopDuration') {
-        edit = {
-          field: 'stopDuration',
-          value: update.value !== null ? new Duration({ seconds: update.value }) : null,
-        };
-      } else {
-        edit = update;
-      }
+      const edit: Exclude<OptimisticEdit, { field: 'powerRestriction' }> = update;
 
       const newState = applyScheduleEdit(
         { arrival: update.row.requestedArrival, stop: update.row.stopDuration },
@@ -422,8 +413,8 @@ const useUpdateTimesStopsTable = (
   );
 
   const updateStopDuration = useCallback(
-    (row: TimesStopsRowNew, durationSeconds: number | null, propagationMode: StopPropagationMode) =>
-      updateCell({ row, field: 'stopDuration', value: durationSeconds, propagationMode }),
+    (row: TimesStopsRowNew, duration: Duration | null, propagationMode: StopPropagationMode) =>
+      updateCell({ row, field: 'stopDuration', value: duration, propagationMode }),
     [updateCell]
   );
 
diff --git a/front/src/modules/timesStops/types.ts b/front/src/modules/timesStops/types.ts
index 9fd07f0b0e5..25881ee8356 100644
--- a/front/src/modules/timesStops/types.ts
+++ b/front/src/modules/timesStops/types.ts
@@ -134,7 +134,7 @@ export type ArrivalUpdate = {
 export type StopDurationUpdate = {
   row: TimesStopsRowNew;
   field: 'stopDuration';
-  value: number | null;
+  value: Duration | null;
   propagationMode: StopPropagationMode;
 };