Always different and wrong currency calculation

[aspirinemaga]

Hey there, my web is running on Joomla 2.5 + VM 2.0.20b

I have a very curious problem with the currencies. It calculates the prices so wrong that I can't find the answer where does it comes from.

Website is up and running multilangual in 3 languages (English, Slovak, Czech) and with 2 currencies (Euro, Czech koruna).

Currency euro is used for English and Slovak language. And Czech koruna is for Czech language.
In my VMComponent > Configuration > Currencies page. I have two types of Currencies configured:

1. Euro with Exchange rate: 1.00000
2. Czech koruna with Exchange rate: 27.80000

So it should calculate 1 euro to 27,8 CZK, but it doesn't, sometimes it convert the price with a currency 28.200, 28.461, 25.421, etc... depends on price. Actually the currency in "convertECB.php" file is extracted from this url: "http://www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml" and it's value is "<Cube currency="CZK" rate="27.498"/>".

I have a price on a product page, displayed in Slovak language with EURO currency and in Czech language with CZECH KORUNA:

on Slovak: 0,39 €
on Czech: 11,1 Kč
11,1 / 0,39 = 28.461

Another product:
on Slovak: 49,90 €
on Czech: 1387,2 Kč
1387,2 / 49,9 = 27.7995

3rd product:
on Slovak: 4,00 €
on Czech: 111,2 Kč
111,2 / 4 = 27.8  <=== THIS IS CORRECT !!!, and should be always like this and not different.

What can be wrong here ? Anyone got the same ? I didn't found anything similiar to my problem on internet.