This is what I’m doing too. Most schools have that line item at close to 3K/year which I think is pretty ridiculous (at least for my son and what he’ll need). I figure if all room and board and tuition are covered he can pay for his own nights out and deodorant. 
I really don’t want to be paying for restaurants when he has an all you can eat plan on campus. It’s not that hard for them to come up with that a couple thousand a year working Summers or a few hours a week during the school year and they’ll probably be a lot more careful with discretionary spending if it’s their money. My high school senior just started working 8 hours a week towards the end of the summer last year and already has nearly 2K squirreled away to take to college and that’s with only saving half. The other half he’s been using for gas and spending money now.