Sometimes, depending on your settings, this feature can cause
issues with your gateway.
The currency in the currencyvalues table with a
conversion value of 1 is the one that determines the value that is passed to
your gateway at checkout time.
If you have a currency that is not
supported by your gateway as this value, you may encounter errors (eg. PayPal
only supports a limited number of currency values).
The best method to
deal with this is to set the currency with the conversion value of 1 in your
currencyvalues table to one that is definitely supported by your gateway. USD is
the most commonly accepted currency and should, more often than not, be set to
conversion 1 in your currency values table.