Hi @janvl,
let me be clear, the problem here is not Net price or Gross price, we can easily make a setting switching between the two.
The problem is that right now IP is using none of 'em. It is just subtracting discounts after tax.
We should first fix this problem, and then we can discuss, what option to give the user, what should be the default, how, where, when…
To make this clear, I invite you to fill an invoice with your data, and see this yourself:
say Net-price is 100
say Discount is 10
say VAT is 19%
As you said:
Netprice-Discount (or before-tax) gets you: 90 + 17.1 = 107.1 euro
As you said:
Gross-price-Discount (or equating-from-the-final-price) gets you: 91.60 + 17.40 = 109 euro
But now get IP, and make this invoice:
it gets you 90 + 19 = 109
and this is clearly wrong, you are getting the wrong tax amount for that net.
