I am not a TT hater at all, but passer rating is very negatively affected by interceptions , and as we know he doesn't throw a lot of those. TT on third and 12 will throw a dump off for 10 yards. That may look good for the passer rating, but it really isn't that effective.
Passer rating also doesn't factor in sacks or scrambles. There are times where his rating should be up because he runs for first downs, but there are also times where it should be down because he will either get sacked frequently, or run out of bounds short of the first down