In this case I'm pretty sure it's not the teacher: I would bet she has no experience with the administration's attitude toward these issues. And our district has a real reputation for expecting everything to work in lockstep.
The thing is, I feel like it's a pretty basic concept that kids with ADHD will behave worse if bored; so even if DD wasn't PG, it would be basic good special ed services to differentiate an area of the curriculum where any ADHD child was much ahead of the group. And I have said as much before. So far my experience has been very similar to beating my head into a concrete wall repeatedly.