Long Calculation within loops

Hi,

I'm facing problems with a FI report. The batch job took approx 4hours for one variant and some variants can't even complete on time. For this case, out of the 4hrs, only 1 hour is due to SQL access.

I've traced the 3hr performance problem to a form which does calculation and sum of figures within loops.

What could be the problem... or what would be a good way to further investigate this?

So far I have only done performance tuning for programs due to inefficient SQL statements.

So, this is something new to me.

Thanks!