How to make the expression into load script?

[#1]

Hi,

Can you help me converting an expression into load script? It kinda fibonacci structure.

sum([Amount Loan])-sum( aggr( rangesum( above( sum([Principal Payment]),0,12) ),Month))

TYPE          MONTH          VALUE          RESULT SHOULD BE

A               Jan                  4                         4

A               Feb                 5                          9

A               Mar                 1                         10

------------------------------------------------------------------------------------------------

B               Jan                 6                         6

B               Apr                 1                         7

B               Jun                 3                        10

I'm lookin' forward for your help.

Thanks,

Bill