Sure he used auto-tune. But to me its not like its a crutch but like to add depth to it. Basically to spice up the song, yes in the live performance it is quite loud, compared to the rest, but I think it has to do with a mix mistake from the playback (god I had using that word). I mean in the original,but its only apparent when you concentrate really hard on it, at least thats how I feel about it. My $0.02. And I guess his insercuitry was that he had no backing band this time, so in other words if something got fucked up it would all be his fault which he was very cautious about.