When an initiatory petition is received by the county board of commissioners to alter or extend within the 18 mill limitation existing separate tax limitations of the county and the townships and intermediate school districts in the county, or when the county board of commissioners resolves to alter or extend within an existing 18 mill limitation existing separate tax limitations of the county and the townships and intermediate school districts in the county, the county board of commissioners shall proceed in the same manner as provided in this act for an original initiatory petition. The county board of commissioners shall notify the persons and bodies having appointive powers under section 5 of the receipt of the petition or the resolution by the county board of commissioners. Those persons and bodies shall select the same persons provided by section 5 for a county tax allocation board to serve as members of a county advisory tax limitation committee that is created. The committee shall meet within 10 days of its selection and shall prepare separate tax limitations for the county and the townships and intermediate school districts in the county, aggregating not more than 18 mills that the majority of the committee considers will provide for the financial needs of the county, townships, and intermediate school districts. The separate tax limitations shall be promptly transmitted to the county board of commissioners and the functions of the committee shall then cease. The question shall be submitted to a vote of the registered and qualified electors of the county at the same time as the separate tax limitations proposed by initiatory petitions. The election, determination of results, and procedure after the determination shall be the same as provided in this act for an election held upon original petitions.