Why was the payoff so much higher at foreclosure?

[Sheryl Williams]

My FHA loan foreclosed with a principle of $140,000. The bank auctioned the property stating I owed $153,000. It was sold for $155,000 and I only received $800 in surplus from the trustee after they took their fees of over half. Does this sound right at all? I thought the trustee would have accounted for their fees already in the payoff from the lender of $153,000 ... also this seems too high, especially considering the impounded insurance payments were not being made. What other fees can this be? Does the final payoff include past due mortgage payments on top of the principle?