(a) The parties may offer evidence as they desire and shall produce additional evidence that the arbitrator considers necessary to understand and resolve the dispute. However, any documentary evidence not properly exchanged between the parties before the hearing will be excluded from consideration unless good cause is shown.(b) The arbitrator is the judge of the relevance and materiality of the evidence offered. Strict conformity to the rules of judicial proceedings is not required. The Texas Rules of Evidence are not binding on the arbitrator but may be used as a guideline.(c) Each party shall produce any witnesses under its control without the necessity of a subpoena. Individuals may be compelled by the arbitrator, as provided under the Texas General Arbitration Act, Texas Civil Practice and Remedies Code, §171.007, to attend and give testimony or to produce documents at the arbitration proceeding or at a deposition allowed under this subchapter, §156.205 (relating to Discovery).