I have a sales invoice report that calculates the no of boxes sent per item some items have different size boxes than others so i have to divide the ammount by ordered ammount then round up. ie ordered 160, box capacity 12 so 160/12=13.33 rounded up = 14 boxes.I then want to calculate total no of boxes sent for the complete order.This I cannot do, I have tried insert total/subtotal for boxesrounded but this is not available as a field although it is in the report.I have tried a formula ie: sum({boxesrounded}) but I get the message "the sum or running total could not be created".I have tried running total with no luck.Whhy is this formula not showing as an available field in order to insert a subtotal.