Report not summing by group correctly

Hello,

I have this Crystal Report whereby I am trying to sum values (summary) by group. The groups are as follows:

The first summation is by the group FatherNum. Without grouping, the results are like this:

This means that the 1st result of the summation by FatherNum should be 568322.78. That is (367,764.23 - 69,441.45)

I have tried to put the summary by right clicking the amount field, inserting summary and setting summary location as FatherNum. I have also tried using a formula: sum({CashFlow.Amount-USD},{CashFlow.FatherNum(1)})

I however get these results:

How do I solve this problem?

Any help appreciated.