161—9.7 (216) Scope of discovery. Unless otherwise limited by order of the presiding officer for discovery in accordance with these rules, the scope of discovery is as follows:
	 9.7(1) In general. The commission may obtain discovery regarding any matter, not privileged, which is relevant to the subject matter involved in the pending investigation, whether it relates to the claim or defense of any party, including the existence, description, nature, custody, condition and location of any books, documents, or other tangible things and the identity and location of persons having knowledge of any discoverable matter. It is not grounds for objection that the information sought will be inadmissible at a trial or contested case hearing if the information sought appears reasonably calculated to lead to the discovery of admissible evidence.
	 9.7(2) Supplementation of responses. A party who has responded to a commission request for discovery is under a duty to supplement or amend the response to include information thereafter acquired as follows:
	  a.   	 A party is under a duty seasonably to supplement the response with respect to any question directly addressed to:
	 (1) 	 The identity and location of persons having knowledge of discoverable matters; and
	 (2) 	 Any matter that bears materially upon a claim or defense asserted by any party.
	  b.   	 A party is under a duty seasonably to amend a prior response if the party obtains information upon the basis of which:
	 (1) 	 The party knows that the response was incorrect when made; or
	 (2) 	 The party knows that the response though correct when made is no longer true and the circumstances are such that a failure to amend the response is in substance a knowing concealment.