This isn't what you asked, but I'll throw out something else to think about. Our kiddo's test scores were beyond what was necessary for early k, but we took the tester's advice and had him go to K with agemates, then skip 1st. The rationale is that K is more fun, more learn to do school, rather than 1st, which is sit more in your chair all day and learn the basics of how to read and do basic math. Also, our son had refused to learn how to write before K, so we figured he would at least learn something there. (He was reading at least a few years ahead by age 4, and could do basic math already.) We let him "play" another year at home, which included a lot of learning.
We did meet with the teacher, principal, and GT coordinator before K and let them know his scores. They did their own testing for achievement, and were going to differentiate. This actually took a lot longer to happen. We finally got the school to agree to test our kiddo on the MAP with the second graders (they didn't have testing earlier at the time). Then they really saw how advanced he was. If you find that differentiation isn't happening, I highly recommend asking for above-level testing to show them what level your DS is working on, using tests the teachers are familiar with. The achievement testing the school psych gave DS before school started was the WJ -- I don't think that means much to teachers. Likewise the IQ test scores were ignored by the teacher - she wanted to get to know him herself. Which didn't work so well for my kid who didn't want to stand out.
And I second the IAS. It's a wonderful objective survey to determine if your kiddo is a good candidate for whole grade or subject acceleration.
Forgot to mention handwriting. Even when my son when to kindy with agemates, his handwriting was among the worst, and skipping first made it noticeably the worst. This restricted his ability to get some needed differentiation since the school refused to let him go to a math class at his level because they claimed he couldn't handle the writing. This was cured by finding a school that said handwriting didn't matter as long as he could make it known to the teacher he understood the concepts and could get him the answer some way. Guess what, DS is now 10 and his handwriting is still rotten -- the grade skip had nothing to do with it... Just mentioning it because handwriting is a big issue with grade skippers, esp. boys.
