3firetrucks, this may be a stupid question, but are you factoring in the exchange rate of the US dollar?
BTW, from what I've read, 20# Blue Rhino exchange tanks are only filled to 17# and Amerigas exchange tanks are only filled to 15#. Things that make you go HMMMMM. Refill stations might be harder to find, but I bet they are a better deal than exchanging tanks, even in Cananda.
I don't need a map, my wife is always telling me where to go.