Have her levels changed somewhat? I haven't browsed the book recently, but on her website level 3 claims "1 or 2 per 100", which is pretty basic 98th percentile gifted or just a hair higher. In the past, she's claimed that DYS kids fall in 3's, 4's and 5's which makes no sense given the quoted rarity for level 3. I can't process the jump from 1:200 level 4 to "more than 1:1,000,000" level 5. I would place DS somewhere in between without shelling out any money,

. I confess, I am curious....but given how little I remember about their early milestones, it's a moot point for me at this stage of the game. And my kids are too old to think back about how I might feel when they were preschool age. I'm following the discussion though as it presents many interesting points.
No, not change there. Level 3 says the book is 98th and 99th, level 4, 99th, and level 5 above the 99th.
So, in that it doesn't make sense to me that DYS would be level 3, unless the scores are inflated as per her explanation in the FAQs listed above.
And the jump is even harder to understand in terms of rarity when t is more personality driven.
The other thing that has not been noted is that her research/book/website seems to focus on more evenly gifted kiddos. She does say that level 5 are globally gifted, good at everything. She doesn't say this about the other levels, but I do think that it is geared more for the balanced kids.
Now, perhaps that is another category of kids that are missed by the assessment: those that are much more gifted verbally or non-verbally than in the other area.