Ed, (that will be easier than mcsquared:[
HG and PG usually needs 2 or more grade acceleration (granted with no 2E issue).
Your DS will be fine after grade acceleration. He probably will need more later on.
I came back to read this because it scares me. My nearly 6 year old son scores >99.9 percentile. At his current school he is unlikely to get anything in the way of acceleration or extension and all the other schools are much the same. If I want acceleration I will have to fight everyone and may make things unliveable with. If I do every other school in town will know before I approach them.
when he is about 11 and changes schools there is an extension class but it is new and I suspect it won't last. Also it is more achievement based and he is likely to have given up by then. I guess I had better get used to fighting the system.