I have a report with two groups and four formula fields. I can sum three of the formula fields by using the Insert Summary button for the different groups, but when I click on the fourth formula the button is disabled. I've tried everything that I know of, Running Total Fields, created a new formula and tried to sum the other formula nothing works. My formula is : CostPrice * 0.1. Is it maybe because I multiply in this formula, the other I only add and subtract?