I'm going to be running some comparison tests but watching the way zpool does its payouts I don't think 24 hours is long enough to get a fair comparison. I think you probably need two or three days for the payouts to stabilize because if you're mining an algo that has a lot of coins, you can have a lot of credit locked up in a half different coin accounts and the payouts are a little wavy even though the input hashpower is constant.

If you have a very small mine it might take more than a few days to get to that point where it's stable.

Miningpoolhubstats is somewhat similar in that only the "Payout Last 24 Hours" for your payout coin really seems to be relevant and it takes a few days to get that number stable before you can see what it actually happening.

The apparent 20% fee may just be because you have about 20% of your coins in other coins that have not reached the thresholds needed to get traded to your payout coin. If you let it hash a couple days you'll have everything topped off and your input hashpower should equate to your output payments.

One thing I like about Miningpoolhub is that you can manually get payments on all your other coins to empty your account so you don't have to wait for them to automatically get traded out. On zpool it looks like it's only automatic trading to get the accounts emptied. Not a big deal but it's a slight difference.