You mentioned that "James' values represent dealer selling prices. eBay prices are not retail prices, and will usually be lower. Are you saying that when an item on ebay sells for $100, James raises the value to $130 for purposes of his book or does James ignore ebay and just use chips shows, private sales and Doug auctions for prices. If James ignores ebay then I would question the usefullness of the price information.

I would think that the most accurate price guide would use sales from EVER conceivable source (ebay include). The price then becomes the overall average.