18When, under section 15, 16 or 17, any member of the Legislative Assembly other than the Speaker performs the duties and exercises the authority of the Speaker,
(a)
every act done by the member in the proper discharge of his or her duties shall have the same effect and validity as if it had been done by the Speaker, and
(b)
every Act passed, every order made and everything done by the Legislative Assembly while the member is acting as Speaker shall be as valid and effectual as if the Speaker himself or herself was in the chair.