MPS & mrp

   when i go ahead EBS material planning ,i miss those problems:

      FG  mps

      SUB mrp

      RAW mrp

 MDS: FG's quantity as 20

(1)MPS advice as : 7 implenent as work order

                               6 implenent as PR

                               4 implement as PR

                               1 implement as PR

                               2 implement as PR

       questions: why the plan aplit? in setting where?why there are PR?i think i have not the capacity planing.

(2)MRP advice as:

        SUB--demand as 7(equal as advice the FG supply which MPS's advice as work order )

                  3 implement as work order

                  1 implement as PR

                  3 implement as PR

       question:why the plan aplit?why there are PR?why the demand cannot based on MDS.