Issue with PO Matched Invoices Exceeding PO Amount

We are encountering an issue with PO-matched invoices in our system. The current setup allows users to create and process payments for invoices exceeding the PO amount.

For example, we have a scenario where:

1. A user creates a 50% prepayment invoice matched to a PO and proceeds with the payment.
2. Subsequently, the same user creates a 100% standard invoice for the same PO and processes the payment.

Despite exceeding the PO amount in total, the system does not restrict the second payment, allowing it to proceed without any error or warning.

This behavior is causing discrepancies and raises concerns about payment controls. Kindly assist us in identifying the root cause and provide a solution to enforce payment limits based on the PO amount.