Bava Batra 105 - Contradictory Statements in Contracts
If the seller says, "I am selling you this amount of land as measured by a rope, be it more or less," - then these two statements are contradictory. "Measured by a rope" does not forgive even a slight variation, whereas "be it more or less" forgives a deviation of up to 1/24 . The second statement nullifies the first. If it was uttered after a while, it is definitely a retraction. Even if it was uttered right away, we assume that he changed his mind. These are the words of Ben Nannas.
However, the Sages say that since he added nothing to clarify his retraction, this may indicate that he understood the contradiction and went back to the first statement - and decided to stop talking and making further mistakes. Therefore, the statement which gives the seller the smaller amount is operative, keeping the money in dispute in the hands of the current owner .
Art: Josephine Bowes - Cornfield near Calais