Thanks for your response! And now I see I edited out part of my post that clarified why I was (mildly) concerned, so I'll put it here: I'm wondering if five year olds, because they constitute the floor of the program, are a special group to whom this rule might not apply.

Given what the page says, I would assume it is ok to have my son tested at 4+ years - but I just wanted to doublecheck, in case someone out there knew something I didn't, before I made a $300-$500 mistake.