If the apportionment commission has failed to submit a plan for its county within 60 days but not less than 30 days after the latest official published census figures are available or within such additional time as may be granted by the court of appeals for good cause shown on petition from the apportionment commission, any registered voter of the county may submit a plan to the commission for approval. The commission shall choose from among those submitted to it a plan meeting the requirements of the laws of this state and file such plan in the office of the county clerk as set forth in section 5 within 30 days after the deadline for the filing of the commission’s own plan or any extension granted thereon.