erp5_simulation: only modify the first movement to have correct value

bt5/erp5_simulation/DocumentTemplateItem/portal_components/document.erp5.QuantityDeliverySolver.py

@@ -75,10 +75,19 @@ class QuantityDeliverySolver(XMLObject):
     result = []
     remaining_quantity = self.getTotalQuantity() - new_quantity
     simulation_movement_list = self._getSimulationMovementList()
-    for movement in simulation_movement_list:
-      movement.edit(quantity=new_quantity, activate_kw=activate_kw)
+    if simulation_movement_list:
+      movement = simulation_movement_list[0]
+      movement.edit(quantity=movement.getQuantity() + (new_quantity -  self.getTotalQuantity()), activate_kw=activate_kw)
       if remaining_quantity > 0:
         result.append((movement, remaining_quantity))
+
+    if new_quantity:
+      for movement in simulation_movement_list:
+        movement.edit(delivery_ratio=movement.getQuantity() / new_quantity, activate_kw=activate_kw)
+    else:
+      for movement in simulation_movement_list:
+        movement.edit(delivery_ratio=0, activate_kw=activate_kw)
+
     return result
 
   def _getSimulationMovementList(self):