When I was in school, I wound up saving a lot of money by living off campus, because I could eat lentils instead of paying $$$ for the required dorm meal plan. If that applies to your situation & isn't already part of your calculations, add a food budget, see if the numbers change.

Do the dorms really suck? Do you need to move out in order to have a sex life or a quiet room of your own or something like that? I think it's worth paying more for an apartment if you're getting a big upgrade in privacy or study space, but not for aesthetics or parties or the ability to have a cat or whatever.