As used in this part, the term:

(a) Fiscal year means the calendar year, or other period of 12 consecutive calendar months. Once reported on one basis, a change in the reporting year shall be effected only upon prior approval by the Office of Labor-Management Standards.

(b) Corresponding principal officers shall include any person or persons performing or authorized to perform principal executive functions corresponding to those of president and treasurer of any surety underwriting a bond for which reports are required under section 211 of the Labor-Management Reporting and Disclosure Act of 1959.