Totaling When Supporting Detail Cells are Blank
If a data cell in Supporting Detail is blank, FreeForm ignores it when aggregating values (instead of assuming that a blank cell means zero).
For example, you might define Supporting Detail to calculate the daily rate of hiring an instructor ($250) times the number of days per month for which you plan to hire an instructor (4 in January, but none in February). The Instructor total for Feb is 250, even though you don't intend to hire an instructor in Feb:
To correctly total values that are aggregated by the * multiplier when some cells are blank, you can leave the Rate cell blank, or enter a zero in the Days cell, instead of leaving it blank:
This causes the rate (250) to be multiplied by 0 (zero), resulting in a value of zero for Feb.