If you ask me I think it's a focus and confidence thing. He's always been confident but the addition of Diggs ability and confidence has propelled Allen to believe more and more. The offense going for 4th downs and more points being scored has grown this.
I think its focus aswell because whatever he is doing now his brain is in the right place, consistently making better decisions and executing. Could well be down to the more calming music he mentioned.. I say this aswell because tannehill has been really good the last two seasons and he has mentioned using meditation.
If the crowd gets him to the 'amped up' point then it may be a problem, but like other people have said in big games last season with the crowds he turned up and played well.
Pittsburg start this season was the only time he seemed a bit off, always seems to turn it round in games aswell so any blips seem only momentary.