Stepping back and just looking at it from afar...
Brady is pissed after the Jets game and registers his complaint to Jastremski (the tweet says as much).
It can be easily assumed that Brady is also therefore pissed that the prep he wants isn't giving him the game ball he wants - it was 2.5 pounds OVER the max and he wants the min, for crissakes!
Jastremski passes it on to McNally - Brady is blaming Jastremski's staff, essentially.
So...McNally on his way to the field in the AFCCG goes into the bathroom and sticks a pin in the balls. He's got no gauge and isn't going for exact - he's just trying to get them to feel more to Brady's liking.
In this very plausible scenario, Brady didn't do anything wrong.
In any scenario, the whole effing thing is a joke anyway: if the league cares so damned much, why were the balls 16 the day after the JEST game?
If these balls represent the integrity of the game, how does McNally get his hands on them before the game, but AFTER the measurements, to begin with?
This whole thing is a WWF-like bag of dung, sorry. And my scenario above is EVERY BIT AS PROBABLE as anything I've seen from the Wells report, and in that scenario, Brady. did nothing more than complain to Jastremski that the balls were over-inflated.
And in that scenario above, every joking/pissed off/whatever text from McNally makes more sense, right?