diff --git a/addons/mrp_account/models/product.py b/addons/mrp_account/models/product.py
index ab44b72b50c..98f0ee2bfba 100644
--- a/addons/mrp_account/models/product.py
+++ b/addons/mrp_account/models/product.py
@@ -60,7 +60,7 @@ class ProductProduct(models.Model):
                 for move in moves_list:
                     value += move.product_qty * move.product_id._compute_average_price(qty_invoiced * move.product_qty, qty_to_invoice * move.product_qty, move, is_returned=is_returned)
                 continue
-            line_qty = bom_line.product_uom_id._compute_quantity(bom_line.product_qty, bom_line.product_id.uom_id)
+            line_qty = bom_line.product_uom_id._compute_quantity(bom_lines[bom_line]['qty'], bom_line.product_id.uom_id)
             moves = self.env['stock.move'].concat(*moves_list)
             value += line_qty * bom_line.product_id._compute_average_price(qty_invoiced * line_qty, qty_to_invoice * line_qty, moves, is_returned=is_returned)
         return value
diff --git a/addons/sale_mrp/tests/test_sale_mrp_flow.py b/addons/sale_mrp/tests/test_sale_mrp_flow.py
index e1b596a7fc0..f19378839fc 100644
--- a/addons/sale_mrp/tests/test_sale_mrp_flow.py
+++ b/addons/sale_mrp/tests/test_sale_mrp_flow.py
@@ -1928,3 +1928,46 @@ class TestSaleMrpFlow(ValuationReconciliationTestCommon):
             {'product_id': self.component_f.id, 'location_dest_id': stock_location.id, 'quantity_done': 20, 'state': 'done'},
             {'product_id': self.component_g.id, 'location_dest_id': stock_location.id, 'quantity_done': 40, 'state': 'done'},
         ])
+
+    def test_kit_cost_calculation(self):
+        """ Check that the average cost price is computed correctly after SO confirmation:
+            BOM 1:
+                - 1 unit of “super kit”:
+                    - 2 units of “component a”
+            BOM 2:
+                - 1 unit of “component a”:
+                    - 3 units of "component b"
+            1 unit of "component b" = $10
+            1 unit of "super kit" = 2 * 3 * $10 = *$60
+        """
+        super_kit = self._cls_create_product('Super Kit', self.uom_unit)
+        (super_kit + self.component_a + self.component_b).categ_id.property_cost_method = 'average'
+        self.env['mrp.bom'].create({
+            'product_tmpl_id': self.component_a.product_tmpl_id.id,
+            'product_qty': 1.0,
+            'type': 'phantom',
+            'bom_line_ids': [(0, 0, {
+                'product_id': self.component_b.id,
+                'product_qty': 3.0,
+            })]
+        })
+        self.env['mrp.bom'].create({
+            'product_tmpl_id': super_kit.product_tmpl_id.id,
+            'product_qty': 1.0,
+            'type': 'phantom',
+            'bom_line_ids': [(0, 0, {
+                'product_id': self.component_a.id,
+                'product_qty': 2.0,
+            })]
+        })
+        self.component_b.standard_price = 10
+        self.component_a.button_bom_cost()
+        super_kit.button_bom_cost()
+        so_form = Form(self.env['sale.order'])
+        so_form.partner_id = self.partner_a
+        with so_form.order_line.new() as line:
+            line.product_id = super_kit
+        so = so_form.save()
+        self.assertEqual(so.order_line.purchase_price, 60)
+        so.action_confirm()
+        self.assertEqual(so.order_line.purchase_price, 60)