Nick, for early SA I think this extremely correct, and for later SA I find it does blur.
But more in the sense where all the grades 9.2,9.4,9.6 have examples that on any given day could sit in each others' holders.
My most stunning book I own, and cannot fathom how the spine is so sublime, is my DS #182 PC copy. It was obviously a completely unread PC copy. Far outstripping many of my 9.8's.
Though saying this, I know the criteria CGC looks for to garner the 9.8 mantle.
The 9.2 rule does make huge financial sense, recently I picked up one of the TTA#40 9.2 WM copies for $1,150, and the PC 9.4 copy offered at the same time for approx $4,500.
The difference in grade, apperance, and price just did't remotely add up.
Though the ped notation, W pages was also a big draw card. It's fair say, those factors make 9.2's very attractive (thumbs u