(1) The filing utility shall provide a witness to testify that the cost statements, working papers, and other supporting data submitted as a part of the filing or maintained by the filing public utility in support of the filing which purport to reflect the books of the public utility do, in fact, set forth the results shown by such books. Rules ARM 38.5.121 to 38.5.180, inclusive, contain a description of Statements A through N required to be filed.