Be it further enacted, That the city property tax rate each year shall be levied on the assessed valuation of all property, real and personal, within the corporate limits, owned by public service companies, as certified to the city by the state Public Service Commission, or similar state agency, and the due and delinquency dates for taxes payable by such companies shall be the same as for other property taxes, except that in any case such tax shall not become delinquent until thirty (30) days after the assessment has been so certified to the city.