PR Issue (how it's available in ORACLE ) ?

ASA, I Have Q :

Approved PR withe 3 Lines > Auto Create PO > Receiving > Receipts > Inspection > Accepted from First Line 1087QTY from 1100 QTY,

from Second && Third Accepted All QTY >Match Invoice With Receipt > Make Payment > Finally Close PO.

But When i Returned  to  PR I Found First Line By 1100 QTY (Accepted 1087)

it's Amount =0

Because it's Canceled  By User, how this happen in oracle on line has partially QTY Accepted And Billed && Payment && Finally Close  ??