Rule 38.5.135 - WORKING PAPERS ON DEPRECIATION, DEPLETION AND AMORTIZATION METHOD(1) Working papers shall include a description of the methods and procedures followed in depreciating, depleting or amortizing plant and recording abandonments by the utility if any policy change has been made effective since the period covered by the last annual report on FPC Form No. 1 or FPC Form No. 2 as filed with the FPC, or the annual report as filed with this Commission.Sec. 69-3-103, MCA; IMP, Sec. 69-2-101, MCA;