Quote from Cache Landing:
I don't mean to upset anyone but let's be real here. They run a business. They charge what the market will bear. Of course it is going to drop slower than it rises. When it starts rising they have no idea how long it will continue to rise and before they know it their margin could be eliminated. It makes no sense for them to wait and see if prices come back down.
Conversely, once the prices have jumped they've proven to themselves that people will pay the higher price. If sales volume didn't slow dramatically when prices went up, then they won't come back down quickly. OTOH, if volume dropped dramatically when prices rose, any drop in oil will be very quickly realized at the pump in the form of cheaper prices. They still have to make money but they want to keep sales volume up too.