(1) Where an obligation fixes a time for its performance, an offer of performance must be made at that time, within reasonable hours, and not before or afterwards. (2) Where an obligation does not fix the time for its performance, an offer of performance may be made at any time before the debtor, upon reasonable demand, has refused to perform.
When Offer Must Be Made
Mont. Code Ann. § 28-1-1207, under Extinction of Obligation by Offer of Performance.
Mont. Code Ann. § 28-1-1207