What I did wrong

Hello!

Trying to take advantage of the surge in ZClassic, I bought some hash power last night in nice hash and started to mine at Suprnova. I bought 3 hours mining at 1 MSol. In my calculations I should get something around 18 coins at the end, but I got just half of that.

In the first 10 minutes I got almost 5 coins (unconfirmed), and the estimates in the pool's dashboard showed I should expect something around 22 coins, but I got only fractions of ZCL each round.

There were some variability in my hashpower during the whole thing, because I got underpriced in the nicehash market. So, it happened that when a block was solved I had practically 0 hash power at that moment. That happened three times, after I raised the price I got the 1 MSol hashpower again and things normalized.

Could you please help me? I can't figure out what I did wrong. It seems a bit easy to just blame the luck (which plays a role in the block reward), but I suspect that variance in my hash power, and maybe some characteristic of the pool, may have something to do.