If you have to create an invoice where someone has paid in advance (Like rent and additional cost rent) and now with the invoice this is "corrected" it would be very useful to have the option for a subtotal.
It should look like this:
Item 1
Itrem 2
subtotal
paid in advance
total
This would be very useful. Kind of funny not to have this feature since the app is called subtotal...
Also it would be nice if you could enter a fixed value as the discount instead of a percentage value.
