If a person, partnership, or corporation is required through compulsory process under section 6, 9 or 20 of the Act issued after October 26, 1977 to submit to the Commission substantiation in support of an express or an implied representation contained in an advertisement, such person, partnership or corporation shall not thereafter be allowed, in any adjudicative proceeding in which it is alleged that the person, partnership, or corporation lacked a reasonable basis for the representation, and for any purpose relating to the defense of such allegation, to introduce into the record, whether directly or indirectly through references contained in documents or oral testimony, any material of any type whatsoever that was required to be but was not timely submitted in response to said compulsory process. Provided, however, that a person, partnership, or corporation is not, within the meaning of this section, required through compulsory process to submit substantiation with respect to those portions of said compulsory process to which such person, partnership, or corporation has raised good faith legal objections in a timely motion pursuant to the Commission's Rules of Practice and Procedure, until the Commission denies such motion; or if the person, partnership, or corporation thereafter continues to refuse to comply, until such process has been judicially enforced.

The Administrative Law Judge shall, upon motion, at any stage exclude all material that was required to be but was not timely submitted in response to compulsory process described in paragraph (a) of this section, or any reference to such material, unless the person, partnership, or corporation demonstrates in a hearing, and the Administrative Law Judge finds, that by the exercise of due diligence the material could not have been timely submitted in response to the compulsory process, and that the Commission was notified of the existence of the material immediately upon its discovery. Said findings of the Administrative Law Judge shall be in writing and shall specify with particularity the evidence relied upon. The rules normally governing the admissibility of evidence in Commission proceedings shall in any event apply to any material coming within the above exception.