I have the same problem and even in french with french developpers it is difficult to explain it. In a trip to canada I saw prices displayed that way in shops : $ 19.95+tax
In France it is forbidden . we have to display all the prices with taxes included.
There are two ways of working with taxes
Taxes added (US, Canada etc...)Or taxes included (france, others etc...)
taxes added :
For each item I input a price
I input a tax rate
In the shop the price displayed is
('DISPLAY_PRICE_WITH_TAX', true) =the result of item price X taxe rate.
With this method the price displayed in the shop is almost always ending with unwanted cents 19.96 instead of 19.95 which is the price I want
('DISPLAY_PRICE_WITH_TAX', false) = item price before tax calculation
Taxes included.
For each Item I input the price I want to see displayed in the shop
I input a tax rate.
The price displayed in the shop is the price I want so everything is ok
On the invoice the tax rate is used to split the final price of the item in two values : item price before taxes and taxes.