NiceHash mining price fluctuate

Since yesterday I am watching the mining fluctuate and going on and off. What is the reason for that? do not want to change price every 1hr. Mining should be stable. I like mining with NiceHash, but this price changes are not nice. Other thing is that I am getting disconections from suprnova. Is it because they are updating pool?

Every pool I tried so far with NiceHash is giving some sort of trouble. Some are not allowing to withdraw even after mining. As an alternative, I have bought a 4 month's contract from @ 0.0125 BTC/hash/s. So far, mined ~0.015 ZEC with 100 hash/s.

Thanks for informations, I was looking around but did not found any suitable solution. Will take a look on that.