The reason why Audit and Corporate Finance always insist for Finally Closing the PO is because it is not possible to perform any action (Receive, Transfer, Deliver, Correction, Invoicing, Returns etc.) on the Finally Closed PO. And moreover it will not be possible to re-open the PO once it is Finally closed.
Whereas, If the PO status is 'Closed' then there is a possibility of re-opening the PO either manually or by performing Returns. This will have an impact on the accounting/accruals if there is any transaction carried out during or after the reconciliations by the Audit or Corporate Finance Teams.
I hope this answers your question.
Does the PO's in closed ( Not finally closed only closed ) status come up in Accrual reports ?
I believe Accrual Report will consider the receipts accrued for the closed PO's as well.
And hence in order to avoid the discrepancy because of subsequent re-opening the PO (either manually or through Returns transactions), it is advisable to have the POs Finally closed. So that there shall not be any further transactions against those accrued lines.
It was nice explanation by Shabbir.
you will find more difference between closed and finally closed when you are using GL budget or projects budget
Example: PO raised for 100 and matched amount is 60
1) if you are only closed the PO - means budget utilized is 100
2) if you are finally closed the PO - means budget utilized is 60 only & rest of 40 can be available