Maybe a tiny handful of two-second bids are counterbids, but almost never. People who bid that late are snipers--like us! Whether they snipe manually or through a service such as AS, does not matter. They are deliberately waiting until the last possible seconds to place their bids. Like us, they know that many eBayers--especially newbies--do not bid their true max, and they are counting on that to avoid last-minute bidding wars. In short, they are employing the very same psyschology that we are. Some of them may even be other AS members.
Steve pointed out, and THIS IS WHAT I BELIEVE MANY FOLKS ARE OVERLOOKING, that the other sniper does NOT know how much your bid is. If you place a high bid, even one with five seconds remaining, your true max is not automatically revealed, only the amount necessary to make you the high bidder. For example, if the item is currently going for $26.50, and your snipe is for $35, your last-minute bid would simply raise the price to $27.50, not $35. If someone else puts in another last-minute bid for $30, then you would still win, but for $31. But if that other sniper placed a bid for $50, then there is no way you can win, since his snipe would raise the winning bid to $36, one increment above your snipe. That sniper had no way of knowing that you bid $35; he simply placed a snipe for a higher amount, and would have done so, regardless of whether or not you bid. The only difference would be in the precise amount paid by the winning sniper.
So, most of the time these are other snipers who were simply willing to pay more than you did. But people who do not understand how proxy bidding works see their own $35 snipe and the winning $36 bid and mistakenly conclude that the other member was responding to the AS snipe, outbidding it by a mere dollar. This misunderstanding is widespread on eBay. I have people who work with me, longtime eBayers, whine that they were outbid "by one freakin' dollar!" I have to explain to them that this is extremely unlikely, regardless of the final amount of thw winning bid. I even have a fellow AS sniper who last week told me the same thing. Even she did not understand proxy bidding! "But how could he know I would bid for $21.50?" she moaned.
This all points back to the same thing. Decide your max well in advance, then bid that at the very last second, through AS. If you win, great--and you will win most of the time, unless you are bidding pittances. But when you do lose, it is usually because someone else was willing to pay more than you were.
