How to Aggregate the Comparing criterias

[Bala_1149216]

Below is the scenario

Order Id	Brand	Contract Period(Months	Time limited discount period(Months	Gross Price	Discount Price	Net Price
123	A	30	6	50	40	10
456	B	12	7	60	30	30

I want  to do the following

if(Contract Period > Time limited Discount duration, Sum(Gross Price - ((Time limited discount duration * Discount Price)/Time limited discount duration))

Above logic will work for straight table , but for pivot or chart it is not working

How to handle it in front end?? Any suggestions