Matching to a PO

I am doing a 3 way match to a PO, matching to the receipt. 

EX. Requested 10, received 9, invoiced for 10 or

Requested 10, received 10, invoiced for 12 or

Requested 10, received 8, invoiced for 6

When I enter the invoice, I enter for what the invoice states as a quantity.  I match to the PO.  When I validate, the system puts a hold on the invoice because of the difference between the Invoice qty and the received qty.  I understand why there would be a hold placed but what is best practice to overcome this.  Do I alter the qty entered for the invoice?  I am not from the financial side, so my knowledge of how this