Confidence. When came to TB, he didn't have much confidence to win even though he could get a mini-break. Last year, last last year, this would never happen.
TB is always good for big servers, but not for Andy, the fastest serve speed owner.
Why he don't have ACES in TB?
To win TBs depend on ACES, big serves and forehand, that's the way for Andy, I believe.
On the other hand, he should also improve the skills to avoid TB. When facing BP, it also needs his confidence.
So Andy, go back to last last year, don't forget your big weapon when improving other skills.