Posting to price difference account (PRD)

Hi,

We had given price control "V" in material master. In PO we had price of 10 and we received the same material at different price.  Now upon invoice the system is posting some amount in the price difference account. We don't want the system to post it in price difference account instead the price to be posted in stock account in the material price.  How can we stop the system to post in the price difference account  (PRD) ?

Thanks in Advance

Mk