Oh, you mean in real life Cricket

Like Coll (and probably many of us), I think there is a massive difference between MG and HG+. Even within that top 1% I think there is a huge difference. In fact I know kids who have scored the same as dd (>99.99) and she is a couple of years ahead of them without any effort on our behalf.
Given that range of ability all looking fairly similar on paper, I have to be honest in saying I don't know what schools can realistically do or where they draw the line.
But on top of that there is this massive push toward tutoring. In Australia there is no mandated requirement to accommodate gifted kids as far as I am aware (there is reference to meeting all kids needs in state policies, but the ones I have read are very broad), so we don't really have the same issues here in terms of determining who gets access to what beyond what families advocate for themselves (at least in primary school - we have selective high schools).
At dd's school kids are being tutored from K. This skews teacher perception of what gifted looks like. Dd's old teacher constantly told me dd couldn't be gifted in math because she couldn't add quickly in her head like the other kids in her class. Dd's testing shows maths to be her major strength and she was working on maths problems 4 grades ahead by her self at home, but this teacher just couldn't see it. She had a who class of other kids reciting what they had learnt at Kumon.
DD changed teachers mid year and I mentioned to her new teacher that the previous one had said she had problems with her computation. The new teacher got her to solve a range of problems using different approaches and said she had no problems with computation, dd just found it easier using visual cues. The teacher said her concern is for the vast majority of kids in her class who are tutored by rote - she said they can answer lots of sums off the top of their head, but give them a written problem and they have no idea how to apply that to the verbal instructions and so don't really understand how to apply what they have learnt.
So when schools are faced test results that show the same thing for two vastly different kids, when they have tutored kids seemingly out pacing the gifted kids and figure they don't need to delve any deeper, I don't know that the gifted label means anything. What you do about that I have no idea (in real world terms).
If I had to draw a line in the sand I'd say in my very limited experience MG kids can be accommodated in the classroom with a good teacher. For HG, perhaps with acceleration. For PG, I personally have not yet seen it work well in our school system at all (but we have a very different system here and I am only going of the handful of PG kids I know from trying to source them as peers for dd).
Sorry, have to run so have not had time to re-read and see if I have made any sense.