Where does your gas come from? Don't you just call in an order and it's delivered?

We buy gasoline 3-4 times per week. It is delivered in transports holding about 9,000 gallons. We can not buy a less than a transport load if we think the price is going down. Circle K delivers to us and they need 24 hours notice. The terminal where most of our fuel comes from is located in Heyworth Illinois. It is about 2 hours away. It would be wonderful if we expected a price increase if we could call and have 20,000 gallons delivered in an hour. It does not work in that fashion. The trucks and time are not available.