Apples to oranges. Nobody is really going to know for sure because there was no before any after numbers. So the argument is moot.
I know your not even supposed to remove the gunk from inside the blower just because you want the seal between the rotors and the blower wall to be as close as it can get to compress the air. Although this is true I doubt he lost HP and even if he did I am sure over time with buildup he will gain in back. It's not like he took a Dremel to the inside of the case.