Thats Right, It's In list prompt on Month(The report is 1 year’s data always), for each month user wants assign 1 parameter, where he can enter
For EX:
January - 100
February-200
March -45
User selected 3 months and assigned 1 value for each month by entering (weather an Input control/ parameter/filter, not coming from database, a manual entry though)
So, now the Report output is 3 months data, each with different calculation as entered by user.
Hope this helps