Puerto Rico refineries are considered federal gasoline producers. If their fuel remains seasonally the same throughout the year, they meet the criteria of a refiner marketing in an area with no seasonal changes, and they are only required to provide three months of data.
In such a case, all fuels would be evaluated by the seasonal Complex Model which matches their year-round season. If the fuel does change seasonally, then they are required to provide data on both the "summer" fuel and "winter" fuel.(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)