Wrong tax calculation

Hello, guys!
First of all thank you for all the efforts to make and support such amazing ecommerce software.

I have a question though.
I have set fixed tax rate 18% for all my product variants.
Main currency is USD, but published currency is Russian Rouble.
One of the items costs 205 USD and it is 6045,98 Roubles (Rouble/USD = 29,4926).

What is not OK: calculated tax for my item is 922,23.
But it should be 922, 27!

Am I missing something?
I am using the version 2.50.

Thank you.

not sure how the currency works but my guess would be it's calculating 18% of the us dollar price then converting to Roubles and you are getting rounding errors?

I'd try changing your dev site to primary Roubles and see what happens.

Thank you for your reply.

I've switched to the roubles as the main currency. In this case tax value is right (922,27).
But it is completely unconvinient for the company to set prices in roubles, because we buy from western suppliers.

If the problem is somewhere in currency convertion, why the item cost in roubles is so precisely converted?

I mean there are no rounding errors in USD to Roubles convertion...

It seems to me that such result is possible
if you round the first interim result of the formula
USDPrice / 118 * 18 * Rouble exchange rate
not by rounding but simply by cutting off all digits after the 4th one...

Is there any way to solve my problem?

dim wrote:
Make sure that when using USD as primary currency the exchange rate for USD is  1

Thank you for reply, Eduardo. USD is exactly 1.0000