But I want to calcuate the total profit margin percentage off the totals for each field not one by one. I guess the one by one statement is a little vague
What I mean is, here's your logic with the correct parentheses:
Code:
[B][COLOR=Red]([/COLOR][/B]total UnitPrice [B][COLOR=Blue]-[/COLOR][/B] total Unit cost[B][COLOR=Red]) [/COLOR][COLOR=Blue]/[/COLOR][/B] Total Unit Price
You have three Sum() calculations, e.g. Sum([ProdUnitPrice]). So you simply substitute the values in your logic with the Sum() as I wrote it above. No extra parentheses needed.