Today I was thinking about how to bid in an eBay Dutch Auction, and I had this revelation. What I learned probably won't affect you, but it is very interesting anyway. The key fact is that eBay Dutch Auctions DON'T use proxy bidding.

I emailed eBay with this exaggerated illustration to learn the scoop for sure: I wrote:
"Say there is Dutch Auction of 5 lots, starting bid $1.

Say:

Mr. A bids $1000 per lot for 5 lots

Mr. B bids $2 per lot for 3 lots

Mr C bids $2.50 per lot for 1 lot

Mr D bids $3.00 per lot for 1 lot

Does Mr A end up paying $5000 for the 5 lots because:

(1) All winning bidders pay the same price per item—which is the lowest successful bid. This might be less than what you bid!

(2) Proxy bidding is not used in Dutch Auctions."

EBay replied that I was correct:
"Hello Robert,

Thank you for writing to us with your question. I'll be happy to help
you with this matter.

You are correct. Because Mr. A bid on all the items available in the
Dutch Auction, he would be responsible for purchasing all the items in
the auction at $1000 per item for a total of $5000."

So the key thing is that there is no proxy bidding in Dutch Auctions. In my illustration, Mr A had to pay $1000 per lot because he bid on all 5 lots. If he just bid $1000 per lot for 4 lots, he would win 4 lots at $3.00 per lot, and Mr D would win one lot at $3.00 per lot."

For more on Dutch Auctions, click this (and maybe you have to scroll up after clicking the link (!?):
http://pages.ebay.com/help/basics/f-format.html#Dutch

Robert