I'm mining on http://gdc.nordicminers.eu/ but it seems I'm getting a quarter of what I should get with 4.6MH/s

With a difficulty that varies from ~3.5k to 6.5k, I should get in 24H something like 10k to 20k GDC, but I'm only getting ~5000

Their pool page is totally misleading, showing that I should get ~20k GDC with a ~5k difficulty, when in a few hours of relative stable difficulty (4.5k to 5.5k), I got ~200GDC per hour, instead of 600 to 800.

This is not the only pool which is completely of (and it's not specific to GrandCoin), showing great profitability when in fact it's much worse than mining standard LTC.