Not sure where you are getting your info, but refineries are not at 85% capacity. They run at 100% of their ability (other than turn-a-round times) all year long.
Sure, margins are not nearly what they were a year or two years ago, but the refineries will not scale back 15% of their business to TRY to affect wholesale prices. It just ain't gonna happen.
BTW, I work for an oil refinery in Southeast Louisiana.