MRP Message Type A

Hi, we are using 9.2 and our users are getting Messages that are Type A in Work with Detail Messages after running MRP R3482.  When I look at the description in 34|MT it shows "Warning Messages" and "User Controlled".

Our user is currently manually entering purchase orders for items with these messages because they will not generate POs. 

Where do we define that a message type A will not create a PO and can that be changed, and what else should we know about that message type?

thank you