Also, I don't know about you, but I don't do well when my sleep (when I can get it) is interrupted, and getting morning phone calls on the days that I do need morning sleep is a pretty good way to get my sleep interrupted. (Agh, I have no idea if I'm phrasing this well.)

You are phrasing perfectly reasonably and I agree with you: I don't find it easy to fall back asleep after being woken by something as jarring as a phone call.

Tutoring, besides being more flexible, also has the advantage of generally taking place in the afternoons or possibly other times during the weekends. (I've only tutored through college centers, not on my own, but the logistics are pretty inarguable.)

Yeah. And I have tutored and I know I'm not terrible at it, so Tiny Wittgenstein applies less there, too.