diff --git a/src/calculation_time_constrains/flows.py b/src/calculation_time_constrains/flows.py
index 4c84797..5f140b3 100644
--- a/src/calculation_time_constrains/flows.py
+++ b/src/calculation_time_constrains/flows.py
@@ -86,7 +86,8 @@ async def create_calculation(
     db_session: DbSession,
     collector_db_session: CollectorDbSession,
     calculation_time_constrains_in: CalculationTimeConstrainsParametersCreate,
-    created_by: str
+    created_by: str,
+    simulation_id
 ):
     calculation_data = await create_param_and_data(
         db_session=db_session,
@@ -94,7 +95,7 @@ async def create_calculation(
         created_by=created_by,
     )
     
-    rbd_simulation_id = "f9ebaf0a-3c41-4cd6-ba60-552c0b303f3f"
+    rbd_simulation_id =  simulation_id or "682c3e83-d471-48fe-9999-c7fa71b2248d"
 
     # results = await create_calculation_result_service(
     #     db_session=db_session, calculation=calculation_data, token=token
diff --git a/src/calculation_time_constrains/router.py b/src/calculation_time_constrains/router.py
index c65f799..903f79d 100644
--- a/src/calculation_time_constrains/router.py
+++ b/src/calculation_time_constrains/router.py
@@ -34,6 +34,7 @@ async def create_calculation_time_constrains(
     calculation_time_constrains_in: CalculationTimeConstrainsParametersCreate,
     scope_calculation_id: Optional[str] = Query(None),
     with_results: Optional[int] = Query(0),
+    simulation_id = Query(None)
 ):
     """Save calculation time constrains Here"""
 
@@ -50,6 +51,7 @@ async def create_calculation_time_constrains(
             collector_db_session=collector_db_session,
             calculation_time_constrains_in=calculation_time_constrains_in,
             created_by=current_user.name,
+            simulation_id=simulation_id
         )
 
     return StandardResponse(data=str(results), message="Data created successfully")
diff --git a/src/calculation_time_constrains/service.py b/src/calculation_time_constrains/service.py
index b50c389..0b10b5c 100644
--- a/src/calculation_time_constrains/service.py
+++ b/src/calculation_time_constrains/service.py
@@ -1094,6 +1094,10 @@ async def get_calculation_result(db_session: DbSession, calculation_id: str):
 
             calculation_results.append(CalculationResultsRead(**month_result))
 
+        optimum_day = np.argmin([month.total_cost for month in calculation_results])
+        scope_calculation.optimum_oh_day = int(optimum_day)
+        await db_session.commit()
+
         # Update fleet statistics
         fleet_statistics['equipment_with_sparepart_constraints'] = len([
             eq for eq in all_equipment 
diff --git a/src/sparepart/service.py b/src/sparepart/service.py
index 79fb367..fa1b4a2 100644
--- a/src/sparepart/service.py
+++ b/src/sparepart/service.py
@@ -396,7 +396,7 @@ class SparepartManager:
             sparepart_id = requirement.sparepart_id
             needed_quantity = requirement.quantity_required
             sparepart_name = requirement.sparepart_name
-            unit_cost = requirement.avg_cost
+            unit_cost = requirement.avg_cost if requirement.avg_cost > 0 else requirement.unit_cost 
             
             current_stock = adjusted_stocks.get(sparepart_id, 0)
             
@@ -968,7 +968,7 @@ ORDER BY lss.asset_location, lss.itemnum;""")
             lead_time=float(req_record.avg_leadtime_months),
             sparepart_name=req_record.item_description,
             unit_cost=float(req_record.avg_unit_cost),
-            avg_cost=float(req_record.avgcost)
+            avg_cost=float(req_record.avgcost or 0)
             
         )
         equipment_requirements[req_record.asset_location].append(requirement)