I understand past payouts are not meaning future will be the same jim, that is down to variance. However they are normally in a similar ballpark, for one to go from 0.01 ish on EU day 1, to 0.005ish day 2 on US, to 0.01ish on EU day 3, to 0.005ish on US day 4, you can see there is a trend occuring to a decent reliability. I am not taking sides, I am merely stating you cannot dismiss it.
I'm a massive fan of the pool, don't take everything as an attack of so personally, a loss of 50% earnings day to day from going EU to USA server is very strange, and not within the realms of variance - as you will be able to see if you look up others payouts.
Cheers
As stated by H2O, the US Server was switching between currencies (even too much), while the EU Server was only mining a single currency (DOGE then LTC). As both server acted (and will continue to do so as long as the EU Server is not patched), making a comparison is like comparing apples and oranges.