You insist on the same over and over again. I think I was clear and I already mentioned the limitations of these estimations. You should discuss this further with the pool admin.

About 0.6 zer/day but as I said, it's a very rough estimation.

Well diff changes all the time so your question has no practical meaning. Also, remember all the other parameters that also influence the outcome. It is impossible for all of them not to vary.

Even so, the algorithm WTM is using for zero is incorrect, so they overestimate earnings. Even their unit is wrong ( H/s instead of S/s ).

As an alternative, pick a miner that has about the same hashrate as you, and check his estimated earnings. Still inaccurate but just as a means of comparison with your own.

Whattomine has been inaccurate for a very long time. A month ago, it was reporting double earnings than the real ones. Now it reports closer to reality, but it is still inaccurate.
Estimating earnings is not that simple and it depends on the time period the average is calculated. If this period is for example one day, the estimations' validity depends on the global hashrate, the pool hashrate, the pool luck, the difficulty and the price of the coin in $. As you may guess, if these numbers fluctuate significantly, then the estimations are quite inaccurate.

For example, you may see that the pool estimates that you will earn 5 coins in 24h. If the difficulty and the increases during these 24h, you will get less coins than expected. If the price in dollars drops as well, then you will get even less dollars!

http://zero.forgetop.com
you can mine here and check your earnings

For me:
Fact, last 24h: 18.02 zer
WTM (with last 24h diff): 18.55

But have some downtime for one or my rigs. Seems legit.

There is definitely something wrong now.