I'm sorry you've already run into somebody who doesn't get and is opposed to grade skipping.
I don't know how far WPPSI can take you as far as mental age goes. We never saw any age equivalents for DS5 IQ test, I didn't even know they do that these days. DS5 was tested at 5 years 4 months and even with the low ceilings for gt kids managed to get DYS score. I just wanted to point out that you can still score really well on WPPSI at the age of 5. Call the psychologist and ask more about the mental age and what score he would have to get in order to have mental age of 7.
I would also strongly suggest achievement testing since IQ is just a number but grade/age equivalents is something the administrators understand much better. Perhaps they meant achievement test age equivalent of 7?
Dottie has quite a good explanation why you want your child to excel as opposed to just pass at the end of the year tests when you are doing grade skip. It pretty much boils down to the fact that you still want your child to be in the top 10% of his new class.
Not all teachers can figure out how far the kids are. Today was my kids' final day in Montessori and I got to take home all they workbooks. They had DS3 doing CVC words, which is really laughable. He could have done this more than a year ago. DS3 reads 2nd-3rd grade books without any problems now. It makes me really wonder how much they got to know him during the year
One more thing. 1/2 K is not that bad as long as you really take it as a social outlet, you know like PreK. Major problems usually start with full day school. If he has to go to K than 1/2 is so much better than full day.
