Basically the propane companies will adjust the propane price depending on the volume used and contract period signed for. The assets they invest in the set up have to be paid for up in some fashion. It can be over a longer contract which would get you better price per gallon or shorter contract would get you higher price. Volume over that period of the contract will play in price as well. In your area we have been seeing the mowers run between 800 gal to 1600 gal depending on how long they run per year. The Cylinder exchange programs are calculated in the same fashion and they look at delivery routes and frequency as well as this plays in the cost to get the cylinders there. Hope this helps.