(1) Data requests and the additional issues process are the primary, though not exclusive, methods of pre-hearing investigation in commission proceedings.
(2) Data requests are a discovery tool, which may contain and combine elements of interrogatories, requests for production, request for admission, and deposition by written question, that provide an efficient means of gathering information where cases are presented primarily through pre-filed testimony with substantial supporting exhibits. Requests—by the commission, hearings examiners, or parties—must be used in good faith, and should avoid repeating previously requested information. Requests must:
(a) describe the topic and to what witness the request is directed;
(b) be consecutively numbered (e.g., the commission may issue PSC-001 through 008 to EWM, PSC-009 through 016 to the MCC, and PSC-017 through 019 again to EWM);
(c) be limited to five sub-parts, denoted with lower case letters (a–e);
(d) have a separate page for each response; and
(e) substantially adhere to this format:
PSC-001 Regarding: Cost of Equity
Witness: Doe, JBD-4:10-25; As Appropriate
(a) Please explain how the current market conditions impact the utility's cost of equity.
(b) Please explain why these market conditions are expected to occur in the future, justifying an increased cost of equity.
(3) When appropriate, the commission or hearing examiner will establish an additional issues deadline to identify issues that the parties have not sufficiently addressed. This deadline will typically occur after the submission of intervenor testimony and before submission of reply testimony. If the commission or hearing examiner identifies any additional issues, it will notify the parties indicating what the issues are, provide direction for how the parties shall address them, and modify the existing procedural schedule as necessary.
(4) Additional methods of discovery available under Montana Rules of Civil Procedure 26(a) are permitted with commission approval. The commission incorporates by reference Rule 26(b), excepting 26(b)(4)(C), which establishes the scope of discovery, and Rule 37, which governs discovery abuses, motions to compel, and sanctions. Nothing in this rule limits the commission's additional broad statutory investigation powers otherwise found in Title 69, MCA.