eBay vs Auction House

[Koufax32fan]

I don't intend for this to be another thread about the virtues of buying/selling on eBay or an auction house, but I was bidding on a somewhat obscure card that just happened to sell on both in the last week or so. I am just wondering how folks react to this (if at all).

I was outbid on 2 auctions in the last 10 days on the same card in the same condition. I was (and still) am looking for a 1937 O-pee-chee (or, are the P and the C capitalized - I digress) Hank Greenberg. Back on October 6, there was this PSA 7 on the Bay that was sold by PWCC for $1,532.77:

http://www.ebay.com/sch/i.html?_from...p2045573.m1684

Last night (or, this morning), this PSA 7 sold on Mile High for a final price (including buyers premium) of $2,010.83:

http://milehighcardco.com/1937_O_Pee...-LOT40251.aspx

So, same card, same condition (per the TPGer) and 30%+ difference in price. There were 17 bidders in the eBay auction, but only 3 bidders were north of $1,000. I actually thought the Mile High card might go for a bit lower than eBay because of the 20% premium and the fact that I believed one of the big bidders was (presumably) no longer in the market. (Of course, someone may be starting a run of 1937 OPC Greenbergs.) The Mile High auction had 12 bids (no idea on how many bidders).

Anyone have thoughts on this?