Bava Batra 104: To the Seller's Advantage

Interactions between buyer and seller - when a seller gives the buyer and advantage, for the portion of land being sold. In whose favor are the adjustments for the buyer or seller? It seems the seller wins out - in that he cannot be compelled to sell.... or so it would seem. Based on the costs of the land. Plus, the amount of land that is a minimum for the sowing of the given measure of seed could lead to a surplus of land that can be returned to the seller.