In our system-
On the basis of historical sales data (atleast 3 months but we prefer 2+years of previous sales data for best forecast accuracy).
1. You can generate the forecast at lowest level(even if you have the data at costumer level then you can forecast at that level)
2. You can run and see forecast at any level
3. 10 category are there so you can categories your hierarchy in that 10 category.
4. You can roll back the forecast
5. You can identify your event/promotions plan- also our system tell you future event percentage(I mean automatic system calculated), so you do not need to define event percentage.