Procedure if heads of families agree as to who are representative watandars

But if in any case described in section 29 * * * the heads of families at any time before the completion of the register prescribed by this Act agree unanimously in writing, or have in writing agreed during the inquiry made in the preparation of the existing registers, as to who are the representative watandars and as to the order of service, then the register, prescribed in this Act shall be prepared in accordance with such agreement.