Section 257 - Reserve for Amortization of Utility Plant in ServiceA. This account shall be credited with amounts charged to account 404, Amortization of Limited-Term Utility Plant, for the current amortization of limited-term utility investments, or to account 435, Miscellaneous Debits to Surplus, for past accrued amortization. It shall be credited also with amounts which may be charged to account 405, Amortization of Other Utility Plant, to account 425, Miscellaneous Amortization, or to account 435, Miscellaneous Debits to Surplus, to amortize intangible or other utility plant which does not have a definite or terminable life and is not subject to charges for depreciation expense.B. When any property to which this account applies is sold, relinquished, or otherwise retired from service, this account shall be charged with the amount previously credited in respect to such property. The book cost of the property so retired less the amount chargeable to this account and less the net proceeds realized at retirement shall be included in account 434, Miscellaneous Credits to Surplus, or account 435, Miscellaneous Debits to Surplus, as appropriate.C. Records shall be maintained so as to show separately the balance applicable to each class of property which is being amortized.D. The utility is restricted in its use of this account to the purposes set forth above. It shall not transfer any portion of this account to surplus or make any other use thereof without authorization by the Department.