Are Work Confirmations designed to be validated like receipts by AP invoices?

Summary:

1. Create a complex PO with 2 lump sum payment schedules and a rate paymet schedule.
2. Create a work confirmation for one of these schedles where I said HALF the work was done.(e.g for the rate payment i said 100 of the 200 pieces was completed)
3. So why does AP Invoices show that 100 is received not 200 - BUT NOT APPLY A HOLD ON THE LINE? It lets the whole amount be paid. I set the lines to 3-way match. (fixed price service line types)

This should not be an AP question - it is more relevant for Work Confirmation/Complex Po behaviour.