Within 540 days after January 2, 1974, the executive committee of the Association shall prepare and submit a final system plan for the approval of the Board of Directors of the Association. A copy of such submission shall be simultaneously presented to the Commission. The submission shall reflect evaluation of all responses and summaries of responses received, testimony at any public hearings, and the results of additional study and review. Within 30 days thereafter, the Board of Directors of the Association shall by a majority vote of all its members approve a final system plan which meets all of the requirements of section
716 of this title.