Preservation age /timecard error in P75A0008

How is the preservation age derived in the Termination screen? We have a paytype if employee is under Preservation age, it should use paytype 900 but it using pay type 902 (above preservation age). Where do we check this?

We also is getting error when clicking Create timecard with Autopay error. From other discussion, it says about PEC. I have checked PEC in BU level and it allows it. The account number defined for the  paytype is BU.OBJ, where else can we check