Indiana Code Title 8. Utilities and Transportation § 8-1-2-63

Sec. 63. Each witness who appears before the commission or its agent by its order, shall receive for the witness's attendance the fees and mileage provided for witnesses in civil cases in courts of record which shall be audited and paid by the state, in the same manner as other expenses are audited and paid, upon the presentation of proper vouchers sworn to by such witnesses and approved by the chairman of the commission.  Witnesses subpoenaed at the instance of parties other than the commission are not entitled to compensation from the state for attendance or travel unless the commission certifies that a witness's testimony was material to the matter investigated.  However, the commission shall have power to pass upon, approve, and limit the expenditures of a public utility in connection with a rate case which are to be charged against the rate base and to be amortized over a period of years as determined by the commission;  it being the intent and purpose to prevent excessive expenditures by the utilities for expert witnesses and for legal and transcription expenses in rate hearings and appraisals.