I think most buyers will bid with an auction hammer fee built into their bid. If I am willing to pay $100 for a figure/set with the hammer fee, I would be willing to pay the same amount for that figure/set if there was no hammer fee, $100.00. And I think that the prices are the market at that given time, a snap shot of sorts. I won several auction lots (about 12) and was pleased with the prices I paid. Like everyone, I have a bid up-to amount that I feel comfortable with and try not to exceed that amount. And what seems like a high price to you or me, might look like a bargain or fair price to another. Like most collectibles, we are in a very thinly traded market. Its not like 100s of any given figure/set show up for auction on a given night. Many of the offerings in OTS's auction may not be offered/seen for auction or sale for months or years to come.
As far as the S&H charges, I would like to think that their cost is pretty close to the actual shipping & handling amount. I would hope that S&H is not a profit center for OTS, and believe that it is not.
Peter