Sorry, Daniel!
I do not understand what "magic" structures you are talking about, what do you mean by "monthly" KPI's.
I am talking about absolutely simple report with accounts in rows and periods in columns. And periods includes Total of the year.
In this report some accounts are normal accounts like NetIncome or NetSales. And finance people also want to have KPI's in the same column. If you calculate and store KPI's using script logic or badi you will see the correct values only on base members for all dimensions and useless figures in Total and other parents.
Hope it's clear.
Vadim