The Valero letter re: CA gas prices -- a question

[ProfessorGAC]

5. Scheduled Maintenance Is A Canard

Refineries use an accounting method that already reserves time (output) from total theoretical capacity.
Unplanned maintenance is, I readily admit, a different issue.
Then refineries do not assume 100% of rated capacity as full utilization. There's always 6% throughput rate above costed rate. The entire petro & petrochem industry does this, as do many other major chemical manufacturers. (Think plastics & solvents, for examples. )
So, other refiners came simply turn up 2, 3, 5% and supply is barely affected.
Finally, if supply were actually tight enough to trigger unwarranted prices, there should be at least SOME minor shortages. Are there regions in California where the consumer can't get gas they need?
If not, S&D is not the real reason.