Iowa Admin. Code r. 199-31.5
For the purpose of satisfying the filing requirements of this chapter, the public utility may request approval to file alternative but comparable information that the public utility files with other state or federal regulatory agencies. If the proposal is approved by the commission, the public utility may file the information as a partial substitute for, or in lieu of, the information stipulated in rule 199-31.3 (476) and the commission may provide that the public utility continue to file the approved alternative information in future filings. The public utility shall file the same information, whether it is the alternative information filed with other agencies or the information stipulated in rule 199-31.3 (476), for at least five consecutive years. Proposals to file alternative information may be filed by the public utility on or before December 1 of the year preceding the year for which approval is sought.
Iowa Admin. Code r. 199-31.5