how to restrict 'To Transact' quantity during backflash equal to Required quantity for a work order

Summary: While doing a Work Order Completion with details, user do the Backflash, where for a component the require quantity let say is 500 no. and To Transact is 500. But as supply sub-inventory does not have 500 on hand instead 450 is available, user has entered 450 only and save the transaction. Here system allow user to save the transaction with less consumption against required quantity.

Content (required): How we can restrict that 'Require' Quantity and 'To Transact' Quantity should be match so that consumption of any component should happen 100% and system should not allow user to save the transaction for the work order execution.