Add negative numbers to positives in aging report

[tanl]

Not sure if this is possible, but I would like to add the negative numbers to the closest positive number in an aging report.

I want to remove those negative numbers so that the customer's overall outstanding is net of the negative numbers.

If the row only has only negative, to replace with 0.

I need from this:

To this:

[Anonymous]

The logic of the calculation is not clear enough. If you want to get answers, please be as clear as possible bearing in mind that you know what you want to obtain and how, others don't.