The metric for calculation is probably off.  I know they recently(within the last couple weeks) changed that in the MPOS code, so I'll see what was done, and what needs to be worked on.  Worst case scenario, I'll change it back to whatever it was before.

Please compare this to what you're actually getting paid on the site though, and let me know.  I'll run some tests as well.

-Fuse

EDIT- Check your hashrate in Coinwarz and see what they estimate.  I think you'd be surprised by the results.