How many books do you submit?
they share their scale but give zero information on how they score certain defects or the guide they used to determine grades.
they do provide notes but I (and many others here) have plenty of books that have received 9.6 grades and zero notes.
9.0 and under, CGC is going to get it right 98% of the time. The real distinction and difficulty (yes, for all of us) is between the higher grades 9.2 and up. Anyone can nitpick and say, "that's not a ____." The hard part is stepping up to the plate and making the right call.