...the issue a little -- the proxy bidding that works for you works for everybody else too!
In your example, you said the winning bid is at $100 when AS places your $150 bid. Well the winning bidder holding the $100 bid may ACTUALLY have a proxy bid at $115. In THIS case, your winning bid would be $117.50.
It is AS's job to place your max bid near the end of the auction. It is Ebay's job to sort thru all the bids and award the item to the person submitting the MAXIMUM bid at the winning bid that is 1 bid increment higher than the 2nd highest bid.
Make sense?
Jabbergah