If it is impracticable for the board to determine from the records the length of service, the compensation, or the age of a member or if a member refuses or fails to give the board a statement of the member's state service, compensation, or age, the board may estimate, for the purposes of this title, the length of service, compensation, or age.
Estimate Of Benefit When Information Incomplete
Mont. Code Ann. § 19-2-901, under Management of Benefit Payments.
Mont. Code Ann. § 19-2-901