The personal attendance of the custodian of the original charts or records specified in the subpoena shall only be required if the subpoena duces tecum so specifies for the purpose of obtaining the custodian's testimony on an issue in dispute and upon payment of the actual and reasonable expenses of the custodian's personal attendance. When the personal attendance of the custodian is requested by a district attorney or an independent or executive agency of the Commonwealth, the fee paid to the custodian shall not exceed the ordinary fee paid to witnesses in criminal cases as specified in section 5903 (relating to compensation and expenses of witnesses) and shall be paid after the custodian's appearance.
42 Pa.C.S. § 6158