ATOMS-820 fixed

lib/views/pages/device_transfer/update_device_transfer.dart

@@ -402,6 +402,7 @@ class _UpdateDeviceTransferState extends State<UpdateDeviceTransfer> {
     _formModel.statusValue = status;
     _formModel.isSender = widget.isSender;
     _formModel.assetTransferAttachments = [];
+    int  workingHours  =  _formModel.tbsTimer?.endAt!.difference(_formModel.tbsTimer!.startAt!).inSeconds?? 0;
 
     if (widget.isSender) {
       _formModel.senderVisitTimers?.add(
@@ -409,7 +410,7 @@ class _UpdateDeviceTransferState extends State<UpdateDeviceTransfer> {
           id: 0,
           startDateTime: _formModel.tbsTimer?.startAt?.toIso8601String(),
           endDateTime: _formModel.tbsTimer?.endAt?.toIso8601String(),
-          workingHours: ((_formModel.tbsTimer?.durationInSecond ?? 0) / 60 / 60),
+          workingHours: ((workingHours) / 60 / 60),
         ),
       );
       _formModel.assetTransferEngineerTimers = _formModel.senderVisitTimers;
@@ -419,7 +420,7 @@ class _UpdateDeviceTransferState extends State<UpdateDeviceTransfer> {
           id: 0,
           startDateTime: _formModel.tbsTimer?.startAt?.toIso8601String(),
           endDateTime: _formModel.tbsTimer?.endAt?.toIso8601String(),
-          workingHours: ((_formModel.tbsTimer?.durationInSecond ?? 0) / 60 / 60),
+          workingHours: ((workingHours) / 60 / 60),
         ),
       );
       _formModel.assetTransferEngineerTimers = _formModel.receiverVisitTimers;