(b) The provisions of
section 13 of the Act, including 13(c) are subject to the general investigatory authority of the Director, Office of Labor-Management and Welfare-Pension Reports, embodied in
section 9 of the Act. The correctness of an interpretation of these provisions can be determined finally and authoritatively only by the courts. It is necessary, however, for the Labor-Management Services Administrator to reach informed conclusions as to the meaning of the law to enable him to carry out his statutory duties of administration and enforcement. The interpretations of the Labor-Management Services Administrator contained in this part, which are issued upon the advice of the Solicitor of Labor, indicate the construction of the law which will guide the Labor-Management Services Administrator in performing his duties unless and until he is directed otherwise by authoritative ruling of the courts or unless and until he subsequently decides that his prior interpretation is incorrect. Under
section 12 of the Act, the interpretations contained in this part, if relied upon in good faith, will constitute a defense in any action or proceeding based on any Act or omission in alleged violation of
section 13(c) of the Act. The omission, however to discuss a particular problem in this part, or in interpretations supplementing it, should not be taken to indicate the adoption of any position by the Labor-Management Services Administrator with respect to such problem or to constitute an administrative interpretation or practice. Interpretations of the Labor-Management Services Administrator with respect to 13(c) are set forth in this part to provide those affected by the provisions of the Act with “a practical guide * * * as to how the office representing the public interest in its enforcement will seek to apply it” (
Skidmore v.
Swift & Co., 323 U.S. 134, 138).