Posting of IR and GR

Dear Expert,

I would like to understand the posting of GR and IR in PO.

Sample as follows:

PO amount  = MYR 4680   (1 pc)

GR amount  = MYR 4680   (1 pc)

Double entry upon posting:

Dr. Exp Ac1     MYR 4680

Cr GR/IR Ac    MYR 4680

IR amount    = MYR 4320 ( less due to discount given) (1 pc)

Double entry upon posting:

Dr. GR/IR Ac     MYR 4680

Cr  Vendor       MYR 4320

Cr  Exp Ac1     MYR  360

In term of Finance,  the entry are tally. However when I view in PO History tab in the PO itself, there is balance of MYR 360. So do at the Status tab of the PO.

In this case, may I know is this the correct posting? Or is there any other way to perform the GR? In order to close this PO, do we need to do force closing by ticking the Final Invoice indicator?

Kindly advise.

Thank you.