With respect to any public service company operating both inside and outside this State, it shall be the duty of the Department of Revenue to apportion for taxation in this State a fair and reasonable share of the value of the company as a system or its rolling stock or flight equipment as appraised under the provisions of G.S. 105-336. Thus, when the Department has determined true value in accordance with the provisions of G.S. 105-336(a) or G.S. 105-336(b), it shall ascertain the portion of the total value subject to taxation in this State by applying property, business, and mileage factors thereto in accordance with the ratio that the company's property, business, or mileage in this State bears to its total property, business, or mileage. In its discretion, the Department may use one or more of the factors listed in the preceding sentence in order to achieve a fair and accurate result in the apportionment of the value of the property of any public service company. As used in this section,
N.C. Gen. Stat. § 105-337