If any tax is levied or general obligation bonds are issued by a city of the metropolitan class as authorized under sections 18-501 to 18-511, the amount of such tax that may be levied by the provisions of section 14-365.01, or the amount of general obligation bonds that may be issued by the provisions of section 14-365.07 by such city must be reduced by the amount of the tax levied or bonds issued as authorized under sections 18-501 to 18-511.