Coings Mined vs Whattomine est coins mined

[East113]

How accurate is whattomine on their est. rewards?

For example it estimates .39 ZEN every 24 hours at my hashrate but I've gotten about .3

That is a pretty large margin of error in my opinion so just seeing if this is a usual percentage.

I'm mining through SMOS with dstm-v0.5.6 on Suprnova pool. 1501 Sol/s.

[Emoclaw]

When given correct data it's usually very accurate. There might have been some changes in difficulty and their calculator hasn't adapted yet, in which case you could input it manually.
But you should also try using CoinWarz's calculators and see if you get more accurate results.
Also, maybe post your hashrate and see how it compares to other people who have the same/similar rig.