The so called 80% rule, back in the day or whatever you want to call it, I used to abuse the heck out of that. Never received a complaint once. I couldn't tell you exactly how long this went on, but know it was at least several months.
I have no problem, if you promise 25 minutes, you should live up to that promise with the exception of, fouling out, being taken into consideration. If you don't agree, then I'm ok with that as well.
But, I think, as in the above situations, if you're going to make the rules so stringent, as to make sure you're hitting your target minutes, for a player not to complain and without any consideration to fouling out, I feel a coach, if using the stamina settings, should have more control over each individual's players's target minutes to make sure he's getting those minutes. One example is "if up or down by 10+ points, game is out of reach etc." then click box to keep player A in game, that way he can get his promised minutes. That's basically all I was really saying.