(1) A utility which elects to proceed under this sub-chapter shall be permitted by the commission to make limited issue filings that do not meet the requirements of ARM 38.5.101, et seq. Such limited issue filings may only be made when the utility experiences a change in costs which exceeds three percent (3%) of the utility's allowed overall return, in dollars, as determined by the last order in the last general rate case establishing rates for those services that are the subject of the filing or the cost of service filing required in ARM 38.5.604(1) (b) , whichever is most recent.