I still think they should have retained the 50/50 centering requirement for perfect.
Remember, under the green system, a 10 wasn’t gem; a 10 meant pristine or perfect.
The gem mint standard (9.5) for the green labels allowed 55/45 one way and 50/50 the other, and the mint was 55/45 all around, so it was possible to get a 55/45 gem mint green. It just wasn’t possible to get a perfect… and it was extremely rare to get a pristine.
So, a green “perfect” needed 50/50 all around. A green “pristine” needed 55/45 one way and 50/50 the other, and a green “gem mint” needed 55/45 both ways.
The black “perfect” allowed for 55/45 both ways, which is where I’ve always held contention. At least, with the CGC switch, they use vague terminology, so no one can really complain about the grade.