price tolerance

- I define purchasing options

price tolerance 30%   and enforce price tolerance

-I define item with list price 200 Eur 

and I create requistion of this item and with price 200 EUR and when I auto create this pr to purchase order and change price to 450 Eur and commit

and when approve the po it give me the price fal with out tolerance and when I change the list price to 400 Eur and return to approve the po still give me the same message how to approve this po with out change enfore price tolerence at purchasing options