Extend lines to invoiced ones

models/sale.py

@@ -17,7 +17,7 @@ class SaleOrder(models.Model):
         Compute the amount (untaxed) that remains to be invoiced from sale order
         """
         for order in self:
-            line_to_invoice = [line for line in order.order_line if line.invoice_status == 'to invoice']
+            line_to_invoice = [line for line in order.order_line if line.invoice_status == 'to invoice' or line.invoice_status == 'invoiced']
 
             untaxed_amount_to_invoice = order.amount_untaxed 
             for line in line_to_invoice: