Should it be determined that the provisions of Tier 4 violate any federal or state laws or the Internal Revenue Code, which render either of such sections inoperative, then Tier 4 shall become inoperative and service retirement benefits and vesting as provided in Section 1504 of Tier 3, and contributions of Plan Members as provided in Section 1514 of Tier 3 shall become operative in their place to the extent allowed by law. If the provisions of Sections 1514 and 1504 of Tier 3 cannot be fully reinstated, then modifications required to comply with changes in the law shall be made by ordinance, adopted in accordance with Section 1624.