Purchase order close is based on quantity or amount

Hi,

In the below scenario what will happen.

Will the PO be closed.

we have 2% receipt and invoice close tolerance.

Does po close ever depend on the amount for a goods and services billed by quantity purchase order line.

1. One pen is ordered for $100 USD

    2 we are invoiced  for $80 USD (they gave us special pricing for some reason)

3   One pen is ordered, one pen is received and one pen is billed at $80 USD

will the po be closed ?

thx,