Customers have asked for years for the ability to over receive purchase orders based on an allowable tolerance. This used to be a fairly straight forward modification in on-premise C/AL but it very difficult with extensions and there really should be stock functionality for this.

An over receive tolerance could be entered globally, by vendor and by items (i.e. 10%)
When receiving the user could enter a quantity to receive greater than the PO line quantity and there are multiple options that have been used to handle the overage
1) Add an additional line to the PO for the over quantity
2) increase the current line quantity and either store the original quantity and/or set a flag for over received.
3) Leave the current line quantity and allow the qty to receive and qty to invoice to be greater than the line quantity.

I have seen all of the above used for various customers with modifications done by ISV's or other partners or by our staff.

This is a very commonly requested function and customers are genuinely surprised this is not a stock function as they have this in other ERP systems thy have used.