The Texas rules of evidence and Texas law with regard to evidence in nonjury civil cases shall apply in contested cases unless Commission rules specify otherwise. Irrelevant, immaterial, or unduly repetitious evidence may be excluded. When necessary to ascertain facts not reasonably susceptible of proof under those rules, evidence not admissible thereunder may nevertheless be admitted by the examiner (except where precluded by statute) if it is of a type commonly relied upon by reasonably prudent persons in the conduct of their affairs. The rules of privilege recognized by law shall apply in Commission proceedings. Objections to evidentiary offers may be made and shall be noted in the record.