Some valid range limits must apply to conventional gasoline because even in summer months the RVP varies widely. The Complex Model contains statistically derived regression equations whose accuracy decreases dramatically when they are used outside of the valid range limits.(7/1/94)

This question and answer was posted at Consolidated List of Reformulated Gasoline and Anti-Dumping Questions and Answers: July 1, 1994 through November 10, 1997 (PDF)(333 pp, 18.17 MB, EPA420-R-03-009, July 2003, About PDF)