No, it's not eluding people (at least not me). As a buyer, GPA is only one of many criteria one can use to determine a price (either the buyer or the seller).
It's kind of like someone using the price of a used car listed in the Kelly Blue Book for a car that's been totalled in an accident. Just because you quote the price listed in the KBB, the buyer can tell by looking at the car that the price is not applicable to that certain car.
At least, that's how I see it. I know I'm not confused if someone lists GPA for a book that is not slabbed. Maybe some are, I apologize if that's the case. :shrug: