This is copied directly from the Pedigree Comics website (bold formatting added by me)...
"Consignors maximize their profits selling in the Grand Auction, more so than on any other auction site or auction house. We do not charge a buyers' premium, an amount that most bidders take into consideration when bidding in other sites (the bidders simply deduct the buyers' premium amount, usually 20% of the winning price, from their final bid, meaning less $$ to the consignor and more to the auction site)."
So, by going with Heritage, he is basically saying that he can get a better return by "giving up" the buyers' premium in the bid, which is 19.5% PLUS pay Heritage THEIR cut of the final selling price (let's use the 5% lowest commission rate Pedigree.com offers on their site since I couldn't find the rate on the Heritage site) and still make more money than what he could selling it on his own website. He is basically saying that his auctions are outperformed by Heritage at approximately 24.5% rate. I feel sorry for people who cosign to the next Grand auction.
Interesting analysis, mike.