((a)) ** Burden of proof** In any proceeding involving the issue of whether or not any person is liable for a penalty under section 6700, 6701, or 6702, the burden of proof with respect to such issue shall be on the Secretary.

((b)) ** Deficiency procedures not to apply** Subchapter B of chapter 63 (relating to deficiency procedures) shall not apply with respect to the assessment or collection of the penalties provided by sections 6700, 6701, and 6702.

((c)) ** Extension of period of collection where person pays 15 percent of penalty**

((1)) ** In general** If, within 30 days after the day on which notice and demand of any penalty under section 6700 or 6701 is made against any person, such person pays an amount which is not less than 15 percent of the amount of such penalty and files a claim for refund of the amount so paid, no levy or proceeding in court for the collection of the remainder of such penalty shall be made, begun, or prosecuted until the final resolution of a proceeding begun as provided in paragraph (2). Notwithstanding the provisions of section 7421(a), the beginning of such proceeding or levy during the time such prohibition is in force may be enjoined by a proceeding in the proper court. Nothing in this paragraph shall be construed to prohibit any counterclaim for the remainder of such penalty in a proceeding begun as provided in paragraph (2).

((2)) ** Person must bring suit in district court to determine his liability for penalty** If, within 30 days after the day on which his claim for refund of any partial payment of any penalty under section 6700 or 6701 is denied (or, if earlier, within 30 days after the expiration of 6 months after the day on which he filed the claim for refund), the person fails to begin a proceeding in the appropriate United States district court for the determination of his liability for such penalty, paragraph (1) shall cease to apply with respect to such penalty, effective on the day following the close of the applicable 30-day period referred to in this paragraph.

((3)) ** Suspension of running of period of limitations on collection** The running of the period of limitations provided in section 6502 on the collection by levy or by a proceeding in court in respect of any penalty described in paragraph (1) shall be suspended for the period during which the Secretary is prohibited from collecting by levy or a proceeding in court.