The commission shall meet for the purpose of considering the apportionments and report made by the board. The commission may readjust the apportionments: Provided, That before any readjusted apportionments shall be confirmed, the commission shall set a time and a place for rehearing and shall give notice thereof and hold a hearing thereon, as provided in section 562, which notice shall also set forth the apportionments as readjusted. The commission shall then issue its order setting forth the several apportionments as confirmed, which order shall be known as the “final order of apportionment”. All further action with respect to the project shall be taken by the board: Provided, That the commission may be reconvened at the call of its chairman, any 2 members thereof, or at the request of the board for the purpose of making any correction or addition to its proceedings within the scope of its powers: And provided further, That the commission shall meet at least once annually. At its annual meeting the commission shall elect a member of the board, approve assessments for operation and maintenance, approve a work plan for the district for the ensuing year, and conduct such other business as is within its powers under the provisions of this act. The commission may appoint such advisory committees as it deems necessary.