banks not taking hits?

It seems that as the days go on banks, especiallymajor ones, are taking less and less hits at auctions. Months ago it used to be that a house that had 400k owed on it would get sold at auction for 160k. The bank takes a hit on the amount owed at over 200k. Nowadays I have seen a bank bidding more than what was owed. It is ludacris. I keep asking, why even have auctions if the bank is just going to buy it back themselves!