Keep in mind that there were 4 sellers listed. If 2 of them were buying the other 2 out, it only sold for 1/2 that. (Only $8450/acre changed hands) 1/4 if you figure the 2 buyers split it.
We had a situation like that around here last mo. Guy buying his 1/2 fm the rest of the family who had been willed the other 1/2. They insisted on an auction, people not in the know thought he was crazy bidding what he did for "junk" land, but in the end it only cost him 1/2 of the sale price.