Did I miss something?

[Sage]

I don't think they cheated, because Nappa's stats didn't change after the current Nappa signed up. Therefore, Nappa's still using the stats the previous Nappa built up, which explains Oozaru and Oozaru Control, which he clearly did not earn.
(No offense Nappa, I'm not blaming you, I'm just stating fact)
I think his stats were never "downgraded" down to the starting stats. So Nappa's not cheating, his stats just haven't been updated.
But as I said before, if someone can prove me wrong, I don't care, but that's the best answer in my opinion.