I run the Stauns on my superduty, and my old toyhauler, but since I was going from 55/65 psi down to only about 15 to 20 psi, I didnt have the problem of them shutting off early because of the lower pressures.
I did have one FREEZE once, airing down in the cold.
I set my stauns using an old tire set to the pressure I wanted, and adjusted the ring until they popped off at the right setting, then just put a slight drop of locktite (pick your favorite color) on the lock ring. Refill the spare tire about 10lbs over your setpoint so you get an accurate pop-off when setting the rings.
The reason the lockring on the stauns moves, is because its the biggest, best thing to grab when screwing them onto your stems. If you dont wrench down the lockring tight, or use a toothpick drop size of locktite, then the whole lock ring, and adjuster move together and throw off the whole show.
I like them, Id get another set. Probably a low pressure set, as I have a high pressure set for the towing setup.