Section 405 - Amortization of Other Utility PlantA. When authorized by the Department, this account shall include charges for amortization of intangible or other utility plant in service which does not have a definite or terminable life and which is not subject to charges for depreciation expense.B. This account shall be supported in such detail as to show the amortization applicable to each investment being amortized, together with the book cost of the investment and the period over which it is being written off.