That would mean that the ECU would have to have some kind of built in engine hour meter... and we would've discovered that little feature long ago... Also, we'd have figured out how to tap into it... instead of wiring in an aftermarket hour meter. Someone would've come up with an hour meter you just plug in to the ECU... Doesn't exist, therefore, this myth is busted.
You also have to figure that a 25% gain in power would be very noticeable... to anyone. Has anyone thought of the fact that after 20 hours or so, a rider gets more used to and comfortable with their quad and starts to push it more?