I've never varied on this one, Bada. It was one of the first things I learned when I started studying jai-alai.
You can over/under in singles, too, but the serve can't be picked, so the serve doesn't have to be altered (as in doubles) to avoid a frontman setup.
And, yes, I AM looking for other reasons.
BTW, the server has an advantage in singles, but that's next week ... lol