Update amount when changing unit or taxes of sale line

Closes #12648

modules/sale/sale.py

@@ -1554,13 +1554,15 @@ class SaleLine(TaxableMixin, sequence_ordered(), ModelSQL, ModelView):
     def on_change_quantity(self):
         self.unit_price = self.compute_unit_price()
 
-    @fields.depends(methods=['on_change_quantity'])
+    @fields.depends(methods=['on_change_quantity', 'on_change_with_amount'])
     def on_change_unit(self):
         self.on_change_quantity()
+        self.amount = self.on_change_with_amount()
 
-    @fields.depends(methods=['on_change_quantity'])
+    @fields.depends(methods=['on_change_quantity', 'on_change_with_amount'])
     def on_change_taxes(self):
         self.on_change_quantity()
+        self.amount = self.on_change_with_amount()
 
     @fields.depends('description')
     def on_change_with_summary(self, name=None):