The Psychology Practice Committee shall not be bound by common law or statutory rules of evidence, or by technical or formal rules of procedure, but may make such investigation or inquiry and conduct its hearing in such a manner as it deems proper and necessary in the premises. The Psychology Practice Committee may, in the event of nonappearance, decide the value of the disputed bill on the basis of the evidence before it. Said hearing may be held by one or more of the members of the Psychology Practice Committee.