Prepayment and Std Invoice with PO matching

User-created Prepayment and successfully matched for all the available items.The customer was able to match the prepayment to PO successfully.

However, when the final invoice was entered and matched against the PO the system assigned a Hold when validating it.

The System Hold applied is “Amount Billed exceeds Amount Ordered”. This means the system is considering somehow the prepayment invoices as amount billed incorrectly.

How to avoid the hold in case of final invoice?