Your definitions are correct, as I understand it. You can look at "A Nation Deceived" for explanations. Our school refused to do subject acceleration and our teacher last year wouldn't differentiate (at least not so that we could tell). Sometimes the 3 gifted kids were given extra homework projects - like a diorama or report with prop but I don't really see that as differentation. Sorry I'm not much help.
I think you have to instigate the accommodation unless the teacher really understands gifted education and your child.
Good luck.
