How many games has TT won when the team gave up 29 points? Let me do the search for you - Zero.
In fact, the Bills have never won a game with TT at QB in which they needed to score more than 21 points.
These are the opposing teams total points in the games TT has QB'd the Bills to wins:
14, 14, 13, 17, 17, 21, 6, 17, 18, 0, 19
That comes out to an average of 14.18 points per game the Bills have allowed in the 11 games they've won with TT at QB. For comparison the league avg. in scoring is 22.6 this year and was 22.8 last year.
When the D has an off day, the team loses. When TT has an off day, the team can still win if the D is playing well. Hell, when the D allows the league average in scoring the Bills don't win. On good teams one side the ball needs to be able to pick it up when the other side has an off day. On the Bills only the D picks up the O.
And I realize TT helps keep those numbers down with the lack of turnovers. But the O also kills the D with all the three and outs and a really bad 3rd down conversion rate. The Bills need more production out of the QB position.