No PP is very limited, PP is suitable for simple deterministic planning that has simple rules. The minute you need to plan more complex issues such as customer grading and capacity of manufacturing facilities then ideally you should follow the SCM route.
In SCM you have two possibilities:
’1 Using Demand planning with custom macro’s and routines to build your planning logic. Basically a super multi-level EXCEL
2 Apply SP CTM (Capable to Match) Logic which satisfies just about all of your requirements