Please verify this for yourself before making any accusations. A few of us have been wondering if the dev fee charged by Claymore is really 2.5% on his Zec miner releases.
We were able to isolate the fees charged by Optiminer, and did indeed verify that the fee was 15% as announced. We used the same method to isolate the fees charged by Claymore. For reference, we used version 4.0 and 5.0 to confirm this behavior. What we found is very surprising.
During (and after) the 90 seconds where it mines for the developer we do notice serious inconsistencies:
- We counted 111 submitted shares in 90 seconds per hour (2.5%) that the claymore mines for himself.
- We counted 15 submitted shares in the immediate 90 seconds after the fee period.
Here is a brief extract of logfiles for the two periods of 90 seconds we referred to. See for yourself:
http://pastebin.com/0EFM8Bat Using various methods, we redirected the "dev fee" workers to Nicehash. We set up static difficulty on the workers and noticed that during the 90 seconds the amount of stale shares increased.
What can we conclude from this? User shares outside of the dev fee period could be used inside the dev fee period. This means that claymore's fee could be as high as 5% (or more).
Because a new block can appear at any time during the "accumulation" period, this would explain why we've been seeing stale shares. They are being gathered from the previous block.
We invite other users to verify this behavior and confirm this theory.
Edit; confirmed wrong. Nicehash ports on Zec aren't working as we assumed for preferred diffs, the miner does mine its dev fee at a lower difficulty. 
