(1) As defined in the Public Utility Regulatory Policies Act of 1978, and for purposes of this rule:

(a) "Automatic adjustment clause" means a provision of a rate schedule which provides for increases or decreases (or both) , without prior hearing, in rates reflecting increases or decreases (or both) in costs incurred by an electric utility. Such term does not include an interim rate which takes effect subject to a later determination of the appropriate amount of the rate.