units per sale report

I have noticed that the units per sale report shows gross units rather than nett units. For example, if I have 3 sales of 3 units but I refund 1 unit then I have sold 2 units nett. However the units per sale report tells me I have sold 3 units not 2.
Is this correct? If so where can I find a report that shows me the nett units?
Thanks
Is this correct? If so where can I find a report that shows me the nett units?
Thanks