diff --git a/contract/models/abstract_contract_line.py b/contract/models/abstract_contract_line.py
index ba84f6f2995..8d89858ad70 100644
--- a/contract/models/abstract_contract_line.py
+++ b/contract/models/abstract_contract_line.py
@@ -217,12 +217,18 @@ def _inverse_price_unit(self):
         for line in self.filtered(lambda x: not x.automatic_price):
             line.specific_price = line.price_unit
 
+    def _compute_price_subtotal_helper(self):
+        self.ensure_one()
+        subtotal = self.quantity * self.price_unit
+        discount = self.discount / 100
+        subtotal *= 1 - discount
+        return subtotal
+
     @api.depends("quantity", "price_unit", "discount")
     def _compute_price_subtotal(self):
         for line in self:
-            subtotal = line.quantity * line.price_unit
-            discount = line.discount / 100
-            subtotal *= 1 - discount
+            subtotal = line._compute_price_subtotal_helper()
+
             if line.contract_id.pricelist_id:
                 cur = line.contract_id.pricelist_id.currency_id
                 line.price_subtotal = cur.round(subtotal)
diff --git a/contract_fixed_discount/models/contract_line.py b/contract_fixed_discount/models/contract_line.py
index 7a1573de6ce..2ce445fc932 100644
--- a/contract_fixed_discount/models/contract_line.py
+++ b/contract_fixed_discount/models/contract_line.py
@@ -33,22 +33,18 @@ def _check_only_one_discount(self):
                         _("You can only set one type of discount per line.")
                     )
 
+    def _compute_price_subtotal_helper(self):
+        self.ensure_one()
+        if self.discount:
+            return super()._compute_price_subtotal_helper()
+        elif self.discount_fixed:
+            subtotal = self.quantity * self.price_unit
+            subtotal -= self.discount_fixed
+            return subtotal
+
     @api.depends("quantity", "price_unit", "discount", "discount_fixed")
     def _compute_price_subtotal(self):
-        for line in self:
-            subtotal = line.quantity * line.price_unit
-
-            if line.discount:
-                discount = line.discount / 100
-                subtotal *= 1 - discount
-            elif line.discount_fixed:
-                subtotal -= line.discount_fixed
-
-            if line.contract_id.pricelist_id:
-                cur = line.contract_id.pricelist_id.currency_id
-                line.price_subtotal = cur.round(subtotal)
-            else:
-                line.price_subtotal = subtotal
+        super()._compute_price_subtotal()
 
 
 class ContractLine(models.Model):