Sale by client

Hi in reports/sales by client, shows the net sale (without taxes) and the total sale (with taxes), but in the total sale the system discount any tax retention (negative tax) applied to the invoice. I think this is an accountant mistake the total sale must be composed of all positive taxes and not taking in account the negative taxes (tax retentions). To really have the right figures should be 3 columns… sale without tax, sale with tax (total sale with positive tax) sales with retentions applied (negative taxes)