Pivot table formula question

[ariel20029]

Hi I have a simple pivot that looks like this:
Sum of hours and max of budget are in the values box in the pivot table. When I try to use the formula builder to calculate the variance = 'max of budget'-'Sum of hours' I am getting an error message.How do I write this formula so it works?


thanks so much
Sharon

Role Rate Sum of hours max of budget
1 100 50 40
2 120 25 30
3 120 5 5