BlessedMommy, we've always shared scores with the school rather than purposely withholding them, but we share with purpose, and to be honest, IQ scores haven't ever really meant much to our school and haven't been terribly useful in advocating - outside of our using them to illustrate the 2nd "e" aspect (disability) and explaining the size of the discrepancy in abilities. Re differentiation, acceleration, gifted programming etc - the piece of the puzzle that teachers and school staff were more interested in has been, almost always, achievement testing administered by the school, or an achievement test that is the same as the achievement tests administered by the school (TerraNova, MAP, etc).
It sounds like you have a good path forward with your school and a good working relationship - I don't hear anything in your post that sounds like you *need* to share private test results at this point in time. If you find that the promised differentiation doesn't happen as you get further into the school year, you might want to reference the test scores when you have a team meeting - but I'd be sure to include work samples and any type of school testing that you have also.
Best wishes,
polarbear
