of certification that is not less than would be produced by the transition contribution rates in effect at the time of the certification. (G) Notice of transition contribution rate The plan sponsor of a legacy plan shall provide notice to the parties to collective bargaining agreements pursuant to which contributions are made to the legacy plan of changes to the transition contribution rate requirements at least 30 days before the beginning of the plan year for which the rate is effective. (H) Notice to composite plan sponsor Not later than 30 days after a determination by the plan sponsor of a legacy plan that a collective bargaining agreement provides for a rate of contributions that is below the transition contribution rate applicable to one or more employers that are parties to the collective bargaining agreement, the plan sponsor of the legacy plan shall notify the plan sponsor of any composite plan under which employees of such employer would otherwise be eligible to accrue a benefit. (3) Correction procedures Pursuant to standards prescribed by the Secretary, the plan sponsor of a composite plan shall adopt rules and procedures that give the parties to the collective bargaining agreement notice of the failure of such agreement to satisfy the transition contribution requirements of this subsection, and a reasonable opportunity to correct such failure, not to exceed 180 days from the date of notice given under subsection (b)(2). (4) Supplemental contributions A collective bargaining agreement may provide for supplemental contributions to the legacy plan for a plan year in excess of the transition contribution rate determined under paragraph (2), regardless of whether the legacy plan is in endangered or critical status for such plan year. (e) Nonapplication of composite plan restrictions (1) In general The provisions of subsections (a), (b), and (c) shall not apply with respect to a collective bargaining agreement, to the extent the agreement, or a predecessor agreement, provides or provided for