In a complaint proceeding conducted pursuant to Iowa Code section 476.3 or in a rate proceeding conducted pursuant to Iowa Code section 476.6, the commission may determine whether a public utility subject to rate regulation is being operated in an efficient or inefficient manner. In making such a determination, the commission shall evaluate the management of the utility in the manner prescribed by rule 199-29.3 (476). Any adjustment to a utility's level of profit (return on equity) or revenue requirement shall be made in compliance with Iowa Code section 476.52.
Iowa Admin. Code r. 199-29.2