I should to find the correct approximation formula.
I have three levels of measurements in my report.
The formula is calculated as follows: VolumeMTD / Number of past working days MTD* Number of working days in all for this month, where MTD - month to date.
My formula works correctly only for the lower level because the number of past working days and total number of working days are loaded in the system only for the lower level.
For next level formula sums working days but it's not correct in my case.