Check your clearing time for the fixer, as that fixing time is quite short for the T-Max films.
And that does seem like a very short wash if you aren't using a wash aid - although TF-4 apparently helps with that.
Will you be printing in a dark room or scanning? I have found that Kodak's guidelines blow out my highlights when scanned. The Massive Development Chart's guidelines do not. I gently invert 4-5x's (5 secs) every minute and then give it a good knock on a hard surface twice to dislodge air bubbles.
My sequence with TMY is an initial 30 seconds of continuous agitation, followed by a 5 seconds every 30 seconds. And when I agitate, I hold the tank with my thumb on the bottom of the tank and my other fingers on the top - I have had tank tops come off while developing film, so I've learned to hold the tank so that can't happen. And to agitate, I flip my wrist so that the tank is completely inverted. I make this a snapping motion, so that in addition to agitation, the tank is also jarred a bit to dislodge any bubbles that might have formed on any internal surfaces. I did this in a teaching darkroom a few years ago, and the instructor went crazy because he thought that it would be too vigorous. Then he saw my negatives and understood that while it may be a slightly different way of doing things, it does work very well for me.
For 4x5 sheets, I use a slosher in HC110 dilution H. Again, I agitate continuously for 30 seconds, and then 5 seconds out of every thirty thereafter. To agitate, I rock the slosher insert inside the tray. The limit is that I don't want to rock the slosher so much that I splash developer out of the tray. I suspect that this is less vigorous than the case with roll film.
Thank you everyone for all your feedback and advice!
I always prewet. ALWAYS. This not only helps uniformity as the developer spreads, but conditions the internal temp of the tank first.
I have always found Kodak's recommendations for agitation too aggressive, more to do with a commercial darkroom than the care and attention you can take at home. If you agitate aggressively you need short periods between agitation because of the possibility of air bubbles forming if the developer foams. So it is a crude means of avoiding the effects of air bubbles and not of avoiding the air bubbles themselves. Kodak wrote the recommendations to be idiot proof which makes sense.
I base all my agitation around thirty seconds initial agitation then three inversions on the minute followed by a swirl as the developer drains back into the Paterson tank. The swirl is instead of a tap on the bench. Variations are made depending on the developer, but I would never go to agitating every thirty seconds which I feel is too close a risk with most films and developers for blowing the highlights.