Auctions go both ways. :shrug:
I have said and still maintain that this book sells very well in private deals at higher prices realized in auctions.
Not to mention that multiple books close in grade skew auction results in ways that are difficult to interpret. It isn't a stretch to believe that if only one of those books were in the featured auction (or there was more than a 4.0 gap between grades) the results would have been different because the competition for the books would have been greater versus split across multiple copies. The auction houses in a way are screwing their consignors and their profits.
Yeah, most of the time, private deals do get stronger prices because the seller sets his/her asking price. If it is a tough book to come by, more so than not, the asking price is firm and price can be steep. Auctions though do have its ups and downs in prices. The obvious downfall would be having so many copies that are around the same grade and ending about the same time. But sometimes, books auctioned off especially in signature auctions, can realize higher prices than what the consignor thought he could've gotten. This is reserved towards harder to find keys for the most part and also for super hot books like AF 15. I have done well both in selling privately and in auctions. In my eyes, it can go either way.