hi,
planning departman have to check undelivered PO's after that you can run updated MRP Area .
1- you can delete or quantity fulfilled in pr
2-ME5A is filtered status 'N,A' , this documents are not related with po. After that, you have to check undelivered po's. You can try ME2N to calculate of po quantity - migo quantity to tick last delivery.
It is done with MEMASSPO tcode.
M.Ozgur Unal