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(2) The rates referred to in subsection (1) shall be based on the service value and estimated service life of plant, as developed by a study of the company’s history and experience and such engineering and other information as may be available with respect to future operating conditions.
(5) A company shall, at any time, upon direction of the Board, conduct a study on the suitability of depreciation rates in use in the light of the company’s history and available engineering data, and shall submit to the Board for approval a report of the results of such study together with recommendations for any desired changes in depreciation rates.
(5) A company shall, at any time, upon direction of the Commission, conduct a study on the suitability of depreciation rates in use in the light of the company’s history and available engineering data, and shall submit to the Commission for approval a report of the results of such study together with recommendations for any desired changes in depreciation rates.