I can;t find the source at the moment...but I did make a post awhile back that showed the numbers to refute the choker perception.
The article said the real porblem was the timing out of things. He do awesome all game, including under pressure. Then a few times just gunslinged himself to an interception.
The law of averages worked against him. You can only come back mircale it so many times.
The Broncos/Peyton manning game is a good example. Everyone remembers he killed the game with last minute interception. Casually forgetting how they were in it all game lone going toe to toe with manning. Just ran out the numbers and clock.
I'll do my best to find it again...I;m sure you'll be interested since I mentioned it.