I think showing the school the types of problems he is doing, and his scores would work better than looking for a 'conversion chart' - afterall, each school has a slightly different idea of what is 'grade appropriate.'
I would 'hothouse' the math facts a bit if you plan to ask the school to give him more appropriate math ( and why wait until next year - BTW?) since most elementary school folks have a very concrete idea of 'what Math is' -
Understanding 'Infinity' would be less impressive than instant math facts in most places - sorry to say.
So in a way, I reccomended some gentle hothousing to help the school 'understand' what they are seeing.
((shrugs))
Grinity
