it's a litte bit complicated to explain, i'm working on this project for a company.

all you have to do is to enter some variables, and the application  do the calculation  by respecting a number of constraints. it's a simple code.

and what drive me crazy is that is working well in my computer  ( the result  is always right ) , and not in theirs.

so please if you have any idea why, i will be grateful for you help.