(1) An offer in writing to pay a particular sum of money or to deliver a written instrument or specific personal property is, if not accepted, equivalent to the actual production and tender of the money, instrument, or property. (2) An offer of payment or other performance duly made stops the running of interest on the obligation and has the same effect upon all incidents of the obligation as a performance thereof, whether or not the title to anything offered is transferred to the creditor.
Effect Of Offer
Mont. Code Ann. § 28-1-1202, under Extinction of Obligation by Offer of Performance.
Mont. Code Ann. § 28-1-1202