A close freind just had his 2005 vette tuned. Dynoed before the tune at 346 rwhp. After 379 rwhp on the same dyno same setting with no other mods. Now I know that the V8 is more forgiving but that over 30 HP from a "conservative" tune according to the tuner. He claims there over 400 rwhp and has the dyno slips to prove it.

The real question is are we error on the safe side...

 

Yes, rotary tuners are conservative b/c most customers don't like this:
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/detonation-%2A%2A%2Apicture%2A%2A%2A-572334/

Dave