Would like to seek advice on the below issue.
There is a question trigger by Auditor.
In Purchase Order, there is GR\partial GR posted but yet buyer could still go into t\code ME22n and amend the item price.
In Purchase Order
Item 10 Material A Qty 5 Unit Price 33.00 (Total Net Price = 165.00)
User posted partial GR
Item 10 Material A Qty 3 Unit Price 33.00 (Total Net Price = 99.00)
Suddenly, Buyer realised that it is incorrect Unit price in PO and went into ME22n and amend the PO price without notice on Purchase Order history tab on partial GR was posted.
Now, in Purchase Order, price change
Item 10 Material A Qty 5 Unit Price 133.00 (Total Net Price = 665.00)
User posted last GR
Item 10 Material A Qty 2 Unit Price 133.00 (Total Net Price = 266.00)
This material is valuated using MAP (V type), hence, it create a lot of incorrect price value due to unit price change. We are thinking to prompt Buyer an error message during ME22n screen on unit price edit once GR\partial GR is done. This will then allow warehouse user to perform GR reversal and then only Buyer amends the unti price via ME22n.
However, what is the steps to configure an error message to prevent unit price change?