DC21 (2E) and DC17 opted not to take these when they were in middle school, so my experience with it is pretty dated. When I took it (group C, I guess), my school didn't budge on acceleration or independent study options. However, it was useful in gaining admission to early college courses and research opportunities at nearby colleges/universities. There aren't a lot of ability-based objections to a young student in community college courses with scores significantly higher than other students in the course...
