As you can see, when you are on the US Server, you accumulate a lot of unexchanged coins to be exchanged later.  When you're on the EU Server, the coins exchange quickly because it's only one currency, and the market is there.  As soon as H2O will have patched the EU Server, it will work exactly as the US Server and switch between many coins, and you will have to wait a bit more before seeing your Balance grow.