diff --git a/src/calculation_time_constrains/service.py b/src/calculation_time_constrains/service.py
index 5859ce7..5071cc8 100644
--- a/src/calculation_time_constrains/service.py
+++ b/src/calculation_time_constrains/service.py
@@ -192,6 +192,21 @@ class SparePartsService:
 
         return projected_stock
 
+    async def reduce_stock(self, db_session, assetnum: str):
+        requirements_query = select(ScopeEquipmentPart).where(
+            ScopeEquipmentPart.assetnum == assetnum
+        )
+
+        requirements = await db_session.execute(requirements_query)
+        requirements = requirements.scalars().all()
+
+        for requirement in requirements:
+            sparepart_id = requirement.sparepart_id
+            quantity_needed = requirement.required_stock
+
+            if sparepart_id in self.spare_parts_db:
+                self.spare_parts_db[sparepart_id]["stock"] -= quantity_needed
+
     async def check_spare_parts_availability(
         self,
         db_session: DbSession,
@@ -221,7 +236,8 @@ class SparePartsService:
             if sparepart_id not in self.spare_parts_db:
                 raise Exception(f"Spare part {sparepart_id} not found in database")
 
-            spare_part = self.spare_parts_db[sparepart_id]["data"]
+            spare_part = self.spare_parts_db[sparepart_id]
+            spare_part_data = spare_part["data"]
             available_stock = self.calculate_stock_at_date(sparepart_id, overhaul_date)
 
             if available_stock < quantity_needed:
@@ -229,18 +245,14 @@ class SparePartsService:
                 shortage = quantity_needed - available_stock
                 procurement_cost = {
                     "sparepart_id": str(sparepart_id),
-                    "sparepart_name": spare_part.name,
+                    "sparepart_name": spare_part_data.name,
                     "quantity": shortage,
-                    "cost_per_unit": spare_part.cost_per_stock,
-                    "total_cost": shortage * spare_part.cost_per_stock,
-                    "description": f"Insufficient projected stock for {spare_part.name} on {overhaul_date} (need: {quantity_needed}, projected: {available_stock})"
+                    "cost_per_unit": spare_part_data.cost_per_stock,
+                    "total_cost": shortage * spare_part_data.cost_per_stock,
+                    "description": f"Insufficient projected stock for {spare_part_data.name} on {overhaul_date} (need: {quantity_needed}, projected: {available_stock})"
                 }
                 procurement_costs.append(procurement_cost)
                 all_available = False
-            else:
-                spare_part.stock -= quantity_needed
-
-
         return all_available, procurement_costs
 
 class OverhaulCalculator:
@@ -418,6 +430,8 @@ class OverhaulCalculator:
                 max_interval=max_interval
             )
 
+            #reduce sparepart stock
+            await self.spare_parts_service.reduce_stock(db_session, equipment.assetnum)
 
             # Aggregate costs
             corrective_costs = [r["corrective_cost"] for r in all_results]