I think it's the opposite, it's like 30% more propane then gas.I think they mean relative. The amount of propane you need to go the same distance in gas is 30% less. I might believe that. There was an article in Peterson's (or Four Wheeler...can't remember) about running on propane. I don't think they said exactly how much cheaper it is since it depends on where you are but they did say it was cheaper. Except that to be able to go the same distance entirely on propane you'd need a big ass tank.