A clear and complete record shall be maintained showing justification for dumping of produce received on joint account, on consignment, or handled for or on behalf of another person if any portion of such produce regardless of percentage cannot be sold due to poor condition or is lost through re-sorting or reconditioning. In addition to the foregoing, if five percent or more of a shipment is dumped, an official certificate, or other adequate evidence, shall be obtained to prove the produce was actually without commercial value, unless there is a specific agreement to the contrary between the parties. The original certificate or other adequate evidence justifying dumping shall be forwarded to the consignor or joint account partner with the accounting and a copy shall be retained by the receiver.