Yep, definitely the dyno.
I had picked up my car Friday afternoon where it had just finished being tuned in front of me, and made 253rwkw...I went to Kamikaze simply to compare the 2 dynos, and made 216rwkw....so just under 40rwkw less, pretty much the same as at least 2 other cars I know the figures of (Al and Nick), who also made 30-40rwkw less than what they normally do.
Not to mention Ron's GTR making something like 70awkw less...