No data in result column in combined report

Hello,

I would like to ask for help.

I have build a combined report with 2 areas: activity history and account history.

Since I needed to create a formula using data from both areas I have created a result column with a formula which considered data from 3 columns (1 from account history and 2 from activity history). I have tried to put there different kinds of formulas, but in each case the result column is empty... Even if I put there some simple formula i.e. saw_2+saw_3+saw_4.

If I put in the formula only one column i.e. saw_3 it works... for all 3 columns. It works also when I put to the formula 2 columns from the same area i.e.