diff --git a/ext/custom-addons/dp_custom/models/sale.py b/ext/custom-addons/dp_custom/models/sale.py
index e486d2ca..45e145dd 100644
--- a/ext/custom-addons/dp_custom/models/sale.py
+++ b/ext/custom-addons/dp_custom/models/sale.py
@@ -56,7 +56,7 @@ class SaleOrder(models.Model):
         for record in self:
             sum = 0
             for line in record.order_line:
-                sum += line.product_id.weight * line.product_uom_qty
+                sum += (line.lot_id.weight or line.product_id.weight) * line.product_uom_qty
             record.weight_total = sum
 
     @api.multi