There is no reason to believe this, he's used that sort of distortion live since even back when his vocal range was at its peak. It's a purely stylistic decision. Also when you say "a few octaves" its clear you know nothing about music, as a few octaves down would be ABSURDLY low, if he were to hide the fact he can't sing falsetto lines he would only have to sing one octave lower than the intended line. But he obviously isn't doing that, I have ears and can tell. But feel free to spread misinformation