a) Yes, provided there is sufficient documentation to calculate the proportion of gasoline produced by the refiner, and, all other requirements of §80.101(d)(4)(ii) are met.
b) The configuration would have to be such that the refiner could, indeed, track the proportion of gasoline used in the oxygenate blend that was produced by the refiner.
c) Same as b).
d) The refiner would have to track the ratio of its gasoline to that produced by another refiner for each batch of oxygenate blend produced.(10/17/94)
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)