Sounds a lot like my DD. We operated on the same principle that we didn't want her to be cruising at the top of the class but striving to reach the top. It was better for her to develop the skills of learning to learn.

It does cost the school nothing but schools often feel that they know much better than you what is right for your child. After all education is their business. Having a gifted child can be rather like coming across a patient who has a very rare condition and walks in with books of information for you. Some schools are grateful for the information and the fact that you have done the work to compile it, some are aggravated that you presume to encroach on their knowledge silo and get narky. I have seen both. Obviously we all hope for the former!