Total_tax modification

[alvarotrapero]

Hello everyone

We have recently seen that the PS total_tax (Version 1.6.1.6) computes them as follows:
[Price of the total without taxes - Price of the total with taxes]

 

Giving as obvious to an error because we already know what PS likes to round. The question is, how can I make orders/payments use the correct tax in this way?

Total_products * 1.21 (We have only this tipe of tax, 21%)
 

We have been able to display the correct order amount in the cart by editing Cart.php like this:

$base_total_tax_inc = $this->getOrderTotal(false)*1.21;

But of course, when confirming the orders the whole process of the BO is done wrong, (the payment shows incorrect total price)
 

*We have already tried changing all the rounding options of the BO

Thanks in advance.

Edited November 23, 2016 by alvarotrapero (see edit history)