Delivery date in Purchase Requisition

Dear experts

I am have created a Purchase Requisition. I have mentioned to delivery date as 31.3.2011 in the PReq. But when i am saving the PR and checking the status in ME5A report (PReq list report). System is showing the Release date and Delivery date as same.

then i have mentioned the planned delivery time in Material master record. what ever no of days i am mentioning there, system is calculating based on it. System is not allowing me to change the information in the transaction level.

Pls help