luckily i got the solution to the described problem:
However, this formula doesn't work with multiple dimensions in a pivot. Attached you will find an example file, with multiple dimensions. The objective is to calculate a cumulative value with respect to Version, Leistungsart and Month. The cumulative and the actual value should both be sensitive to selections in Year and Period. Meaning, that only the values that i see should be cumulated.
I would really appreciate a solution to this problem!