Any hearing which the commission has power to hold, except matters pertaining to rate changes, may be held before any one or more of the commissioners, upon condition, however, that such commissioner or commissioners shall have been authorized by the commission to hold such hearing. Each hearing before any such commissioner or commissioners shall be deemed to be the hearing of the commission. Any determination, ruling, or order of a commissioner or commissioners, upon any such hearing held by him or them shall not become effective until due notice has been given to the commission and the Office of Regulatory Staff and it has been approved and confirmed by at least a quorum of the commission and ordered to be filed in its office with a copy to the Office of Regulatory Staff and any determination, ruling, or order involving the fixing or regulation of a general schedule of rates shall not become effective until due notice has been given the telephone utility concerned and an opportunity has been given the utility and the Office of Regulatory Staff to be heard before at least a quorum of the commission, and the determination, ruling, or order has been approved and confirmed by, at least a quorum of the commission. Upon such confirmation and order, such determination, ruling, or order shall be the determination, ruling, or order of the commission.