We are just starting to face this situation, with a SSA (three classes, two grades above age level) older child and a five year old who is about to need advocacy (they still have him identifying letter sounds with the rest of the class and working on simple word identification; he just read most of a 200 page book).
In our case, although I'm not looking forward to approaching the well-intentioned K teacher, I know that the school already has been pretty good regarding the needs of ODS. They are not going to be shocked to talk about a younger child who has similar needs. In fact, the principal told us when we enrolled him to let her know if he needs more...
So, the school may not be looking at this the way you are looking at it!
