DD scores in the low average or below average range for math fluency (probably around the 20th percentile). I think it's a little better when she is fully medicated for ADHD but still not great. Since there is a large gap between fluency and conceptual ability and she also has slow writing, neuropsych called it slow processing speed. She tested around the 35th percentile on the WISC IV for processing speed, but then a year later was more like the 85th percentile (I'm wondering if that was an error since the school psych was incompetent and never gives kids the WISC IV). At any rate, the neuropsych said that she should be placed at the correct conceptual ability level and be given accommodations for the slow processing/poor fluency. He did not give advice to keep drilling on the fluency. Basically, it's probably never going to be quite normal because she is not retrieving the facts quickly enough from the messed up filing cabinets in her brain. She has documented executive functioning deficits/ADHD. I'm not sure what he would say about a kid who has no other evidence of a disability. It is possible that he will improve if he practices enough. DD improves with practice, but she tends to lose most of the gain after a short period of time has gone by. The school has her accelerated to 6th grade math (she should be in 4th grade based on her age). In the past she was actually accelerated higher, but I wanted her moved down because she was way too slow and it was making her anxious. I think there needs to be a balance between meeting the needs of the giftedness and addressing the disability or weakness. It's easy enough to say "let's just make accommodations" but you can't learn something like Algebra properly if you are cutting out 80 percent of the practice or test questions.

BTW, DD constantly fidgets with everything she can get her hands on and it tends to drive teachers crazy because it looks like she's distracted by these things that she's fidigeting with, but DD claims it actually helps her to focus. The other day she came home from school and her jeans were covered with drawings (in pen). She must not have had paper on hand to doodle on.

In terms of whether misbehavior is caused by boredom or something else, it could be either. DD has a really hard time getting work done in class because of a combination of focus issues and anxiety. Have you noticed this behavior at home, when he does homework? If he is able to complete the work quickly at home, then there is something about the school environment that is causing things to go awry. I do think it's a legitimate concern on the part of the school, and I also think that boredom is unlikely to be causing the problem unless he is finishing everything really fast and then doesn't know what to do with himself. It doesn't sound like that's the case and I suspect he may still be clowining around even if given more challenging work (of course I know next to nothing about him, but it's just a gut feeling based on what you said). It could be that the processing issue with math facts is causing him to lose focus with math, and that perhaps the somewhat chaotic environment of a classroom is making it worse. That's what I think is going on with DD at any rate.
I think it is worth it to think about this issue and whether it is going to cause a problem if he is accelerated with no accommodations. If he is just slow when a timer is involved (maybe because the timer stresses him out?), but you think he actually is fluent with the facts otherwise, then that shouldn't be a problem and I would push the school on that.