Eh, maybe it's different for people that only have to fill their tank every 3-4 weeks. I need to refill at least once per week so it's rare I save any significant amount of money filling up 2 days before I regularly would.

I'm also not sure why everyone would have the same price in mind to start immediately filling their tank at the "cheap" price to trigger a 12% increase amongst 8 different chains of gas stations all at the same time.

Many would be waiting for a few cents more or already pulled the trigger a few cents before.

I just don't think gasoline follows most free market supply/demand rules as much as most things.