Stop Operation on Deviation of Qty in Sales Module

Hello Experts!

Please help us solve issue of accepting deviation of Qty in Sales Modules. For example, we created:

1. Sales Quotation - 10 Qty
2. Sales Order - 10 Qty
3. Delivery: 1st Delivery - 5 Qty; 2nd Delivery - 6 Qty - (due to human error)
4. Successful Operation!

The processes above shows an inadequate Qty based on orders and this is critical on business process. Please help us what to do. It must prompt an Error Message that it deviates on based qty. and then stop the process to correct the qty.

Thank you very much!

Fernz