Can anyone definitively tell me if you are better off cost-wise filling your tank at the local CO-OP vs exchanging it at Menards? The guy at the CO-OP this morning just hooked it up and let it run until it was topped off I assume. He did not weigh it or anything like that. Then it was a flat rate $21.40. I've heard that the exchange tanks are not filled all the way etc. Just wonder what you all think or do in this case. I just bought a nearly new tank this morning from a fella on craigslist for $10. So I've got $31.40 into a new tank so I have a backup for smoking/grilling.