Wouldn’t surprise me if they didn’t do well in school at all. Lots of the truely great artists “fail” in that department. Tarantino quit high school. Chess genius Bobby Fischer quit school at the age of 15 because he “didn’t see the point”. I think many of those that are really good at what they do don’t really care much about school and beyond, if the speciality they are good at doesn’t require the usual academic path.
Or… Simon and Raja and Benji and all those people at Twisted were really good or simply ordinary students and went to college or a university and all that. I believe Raja mentioned something about attending classes at a university in New York on the Shpongle DVD. I might be mistaken, though.
In any case, I also believe that school, high school or college has nothing to do with the supreme skill of creating great music that these artists undoubtedly possess. Nothing at all.