turnaround decisions are scheduled years in advance.....to smooth out the supply curve. while turnarounds may be delayed for market reasons...that is very rare for the majors becuase it's a jigsaw puzzle with dozens of pieces....all the turnarounds in all the refineries are scheduled with a view to maintaining product flow, so if you delay one, you throw the whole schedule off for years.
there is also a danger that if you push the turnaround schedule....and delay it for too long, you get to the point where you have to shut down for maintenace, in an unscheduled turnaround that really screws up the system.
point being about the best you can count on long term is 90% utilization or a bit more.
