At any time, 10 or more days prior to a hearing or a continued hearing, any party or the Commission may send by registered or certified mail or deliver to the opposing parties a copy of any affidavit proposed to be used in evidence, together with the notice as herein provided. Unless an opposing party or the Commission at least five days prior to the hearing, if the affidavit and notice are received at least 20 days prior to such hearing, otherwise at any time prior to or during such hearing, sends by registered or certified mail or delivers to the proponent a request to cross-examine the affiant at the hearing, the right to cross-examine such affiant is waived and the affidavit, if introduced in evidence, shall be given the same effect as if the affiant had testified orally. If an opportunity to cross-examine an affiant at the hearing is not afforded after request therefor is made as herein provided, the affidavit shall not be received in evidence. The notice accompanying the affidavit shall set forth the name and address of the affiant and shall contain a statement that the affiant will not be called to testify orally and will not be subject to cross-examination unless the opposing parties or the Commission demand the right of cross-examination by notice mailed or delivered to the proponent at least five days prior to the hearing if the notice and affidavit are received at least 20 days prior to such hearing, otherwise at any time prior to or during such hearing. (1949, c. 989, s. 1; 1957, c. 1152, s. 3; 1963, c. 1165, s. 1.)