You most likely had the high bid at a lesser amount than the $15.00. Say $9.00. Then at end of auction "Fellow WI Chipper" bids $15.01. This bid will prevail one cent over you because he sniped over your bid of $9.00, thus the bid increment was met and his high bid of $15.01 was over your bid of $15.00.

If your high bid of $15.00 was displayed as being the high bid he would have had to bid $15.50 to win the auction.

Mark