if someone had a company lets call it Company A and they bought from Company B. lets say they bought 100 units for 20 dollars each so the value is 20,000. if some if that was damaged and the company offered 5% allowance on the total purchase but Company A already sold some of their product. Is the allowance calculated on the 100 units, or how many units they would have remaining? like would you do 100-20 X 20 X 5%?