Created attachment 342372 [details]
Simple test file. look at bill 000001 and invoice 000002

When including an expense to a bill with tax included it will nicely calculate the tax and net price. But when charging back to an invoice it will use the price I entered (including tax) to the invoice instead of the net price without tax.

This is only an annoyance and source of error when the tax rate is the same on bills and invoices since I can mark in the invoice that the tax is included. But it does not work when the tax rate is different. 

The chargeback should always be based on the net price without taxes.

Attached is a test file and the screenshots of the bill, invoice and printed invoice