Um, yeah.. no. Look, yes, it's still your house and your rules. And yes you are paying the bills. But you really think it is appropriate for a college kid (or even an 18 year old high school kid) to have such strict limits on his video game time? I mean, sure, do what you want. People can make different choices here.
But, this seems to be an issue more aptly aimed at your younger 2, who are of the ages where they *should* need a adult helping them manage their time. Your eldest *should* be at an age where he is or HAS learned to manage his own time well enough, that he can decide for himself if he can spend time of video games (during the week, late at night even...).
Yes, by all means, you are correct it's your home and you make the rules. And he should be grateful that you are providing him continuing room and board. Even with restrictions. But I have to wonder what the goal is here. To be arbitrary and make it easier on you or your younger kids? Or to help your eldest mature and learn to manage for himself? Maybe somewhere in between.
He still has the urge to lord such privilege over his younger siblings. That sounds awfully immature. Until you stop and realize that some siblings just tease each other that way forever in fun. Or that maybe it's because he doesn't HAVE many such distinctions from them. He feels as if he is VIEWED BY YOU as their age as well? could that be part of it?
I have a 17 and a 14 year old at home. They have different rules. When they were little they shared a bedtime. And a bedtime routine. But as kids grow up, their needs and abilities to manage for themselves change.
If it were me, I would allow him additional privileges here. Why not? How hard would it be, really, to tell your younger kids, "Sorry, he's a college boy now, he's earned it." Or, "when you are 18, you can manage your time for yourself as well." I mean it. Really, you are talking about making it easier on you. Not on what is right or fair. It's not so different than, "yes, he can drive the car, because the state issued him a driver's license and they didn't issue one to you. When you are old enough, you can take the test as well..." Or did you not feel your younger kids would understand why the rules changed about that?
He's not 12. He's of the age where he can leave your home and never come back and there is nothing you can do about it. So why not treat him with a little bit of respect that he is a man. *WE* all know that he's an overgrow kid in a man's body, but in his mind, and legally, he IS a MAN. Not a child. I've found with my own son, that treating him like a man gets better results. Treating him like a child gives me a surly, offended, disinterested son.