How can I create a dimension member formulas involving parent member?

Hi everyone,

I'm trying to learn BPC- Planning and I've got the following issue:

Behind each key figure is a calculated formula which will not be calculated in the aggregated parent member ( Energie Kosten). It's a IF formula based on percentage. As far as I understood it's not possible in BPC NW 10.  to store values at parent level and parent member doesn't aggreagte child values that are calculated members. What can I do to solve the problem? The only solution will be the logic scripts?

Any input is appreciated.

Thank you!