I have two kids that look very different but actually have the same FSIQ. Their GAI's are ~10 points apart but both should have had extended norms and didn't so it could be more/less.
They are sooooooo different. I will also point out that neither of them looked remotely like your DS5. Neither read particularly early (in fact DS was pretty late but when it eventually clicked he went from 0-60 in 2 seconds).
We mostly tested DD to be fair and because she shared genes with DS. DS screams gifted from every pore, by comparison she doesn't but on paper they are far closer than I would have thought.
