diff --git a/addons/sale_product_matrix/models/sale_order.py b/addons/sale_product_matrix/models/sale_order.py
index 6ce55c5ddf0..8c31ee77a53 100644
--- a/addons/sale_product_matrix/models/sale_order.py
+++ b/addons/sale_product_matrix/models/sale_order.py
@@ -45,6 +45,7 @@ class SaleOrder(models.Model):
         if self.grid and self.grid_update:
             grid = json.loads(self.grid)
             product_template = self.env['product.template'].browse(grid['product_template_id'])
+            product_ids = set()
             dirty_cells = grid['changes']
             Attrib = self.env['product.template.attribute.value']
             default_so_line_vals = {}
@@ -64,8 +65,14 @@ class SaleOrder(models.Model):
                 old_qty = sum(order_lines.mapped('product_uom_qty'))
                 qty = cell['qty']
                 diff = qty - old_qty
+
+                if not diff:
+                    continue
+
+                product_ids.add(product.id)
+
                 # TODO keep qty check? cannot be 0 because we only get cell changes ...
-                if diff and order_lines:
+                if order_lines:
                     if qty == 0:
                         if self.state in ['draft', 'sent']:
                             # Remove lines if qty was set to 0 in matrix
@@ -95,7 +102,7 @@ class SaleOrder(models.Model):
                             # if len(order_lines) > 1:
                             #     # Remove 1+ lines
                             #     self.order_line -= order_lines[1:]
-                elif diff and not order_lines:
+                else:
                     if not default_so_line_vals:
                         OrderLine = self.env['sale.order.line']
                         default_so_line_vals = OrderLine.default_get(OrderLine._fields.keys())
@@ -108,10 +115,14 @@ class SaleOrder(models.Model):
                         product_uom_qty=qty,
                         product_no_variant_attribute_value_ids=no_variant_attribute_values.ids)
                     ))
-            if new_lines:
+            if product_ids:
                 res = False
-                self.update(dict(order_line=new_lines))
-                for line in self.order_line.filtered(lambda line: line.product_template_id == product_template):
+                if new_lines:
+                    # Add new SO lines
+                    self.update(dict(order_line=new_lines))
+
+                # Recompute prices for new/modified lines
+                for line in self.order_line.filtered(lambda line: line.product_id.id in product_ids):
                     res = line.product_id_change() or res
                     line._onchange_discount()
                     line._onchange_product_id_set_customer_lead()