23.4.5.7.4For purposes of Sections 23.4.5.7.2(b) and 23.4.5.7.6(b), the ISO shall identify the Unit Net CONE projected for a Mitigation Study Period using: the most recent inflation index.  For purposes of Section 23.4.5.7.4, the inflation index shall mean the average of the most recently published median Headline Consumer Price Index (CPI) and Headline Personal Consumption Expenditures (PCE) long-term annual averages for inflation over the ten years that includes the last year of the Mitigation Study Period, as reported by the Survey of Professional Forecasters, unless this index is eliminated, replaced or otherwise terminated by the publisher thereof.  In such circumstance, the ISO shall utilize the replacement or successor index established by the publisher, if any, or, in the absence of a replacement or successor index, shall select as a replacement a substantially similar index.