Are they the most expensive amongst auction houses now? More than Sotheby's or Christie's???
It does seem like a high number, but it's definitely not the highest. Sotheby's charges a 26% premium and Christie's a 25% premium on all their auctions. Those extra percentages add up quickly. Of course, Heritage has averaged over $150 per lot on prices realized for some time now, so the actual percentage of auctions it affects is fairly low.
But can you blame them for not wanting to waste time and lose money dealing with less expensive posters? Even Bruce has put tons of restrictions now on consignments they accept to try and stop the sub-$20 item losses (and it's helped a lot as he more than doubled his average sales price last year).
The real savings though comes from the fact that Bruce is paying all of our sales taxes for us. He long ago smashed most reporting requirements for sales tax (heck, the Frankenstein TC alone qualifies in many states) but has been eating that for us. That is an extra 6-12% in many states that is not being passed on to us. None of the other auction houses are nice enough to do that.
Plus of course, Bruce's great packing and lower shipping fees. Many other auction houses use shipping to pad totals, I recently paid over $100 to ship a few folded posters from an LA auction (in addition to their 25% buyer's premium), which is just silly.