It's a bit of a shame that ADD isn't a thing anymore, just dropping the H makes it a lot less misleading. The attention deficit part is broadly descriptive of my issues
I do find it odd that it settled into ADHD-I, ADHD-H and ADHD-C; the one that is primarily expressed through hyperactivity literally is called "Attention Deficit Hyperactivity Disorder - Hyperactive".
Removing the H and using the subtypes would add clarity for sure.