If it doesn't cause major problems, it's not a disorder. DS6 "hyperfocuses" and tunes out the rest of the world when he is absorbed in something and (other than aggravating me at times) it probably helps him more than anything. And he doesn't come close to having ADHD.

Anyhow, D&C, I think your point is good - that ADHD causes difficulty regulating attention, not just distractibility.