On Zen Cart 1.5.7d and 1.5.8.
I recently set up taxes for all products. Before I did not do this and this problem did not exist.

I have a product with a net price of 945.4545.
There is 10% tax, so the gross price is 1040.
There is no decimal for the currency I use.

When I put one of this item in the cart, the price displayed during checkout, email and invoice is 1040.
When I put two of those products in the cart, the price in the shopping cart is 2080, at the checkout_payment, checkout_confirmation, mail and invoice it is 2079. Obviously this is wrong and it should be 2080.

Anybody has any idea how to fix this?