If a contractor's bid was low because he made a mistake in addition when totaling the estimated costs, any contract resulting from the bid may be rescinded. When both parties are mistaken about the same material fact, the contract can be rescinded by either party. A word or term in a contract may be subject to more than one reasonable interpretation. Read Raffles v. Wichelhaus . If a mutual mistake concerns the future market value or quality of the object of the contract, the mistake is one of value, and the contract normally can be enforced by either party.
VAlue is variable.
Depending on the time, place, and other circumstances, the same item may be worth considerably different amounts. At the next moment, the value may change. A mistake as to value will almost never justify voiding a contract. Each party is considered to have assumed the risk that the value will change or prove to be different from what he thought. Without this rule, almost any party who did not receive what he considered a fair bargain could argue mistake.