Probably because people are bidding too much too soon. Bidding in the last 30 seconds is the way to go, you get it cheaper and dont knock it up prematurley.
If some guy puts a maximum bid of 200 down when its at 99 cents it will almost surely get bumped up to 200 needlessly before the end
...or if someone advertises the auction on a website full of nerds it will needlessly go up as well. :emperor