The fee is not negligible on Genesis Bitcoin mining. It amounts to around 25-30% of your income. E.g. with 5TH/s its 0.00028 * 5000 = 1,4usd/day - and you are earning 5.40 usd per day, so yeah: 25% with your example but at the moment its more like 30%.
RE: Why Hashing24 or Genesis Mining? A Comparison of Cloud Mining Versus Mining at Home