All proceedings conducted by the arbitrators shall be in conformity with the contractual obligations of the parties. The arbitrator shall comply with Sec. 1404.4(b). The conduct of the arbitration proceeding is under the arbitrator's jurisdiction and control, and the arbitrator's decision shall be based upon the evidence and testimony presented at the hearing or otherwise incorporated in the record of the proceeding. The arbitrator may, unless prohibited by law, proceed in the absence of any party who, after due notice, fails to be present or to obtain a postponement. An award rendered in an ex parte proceeding of this nature must be based upon evidence presented to the arbitrator.