I went to exchange my 20lb tank today and noticed that Home Depot only fills their tanks up 15lbs! That is 25% less than I thought I was paying for, so on my way home I stopped for gas and saw the gas station only fills their tanks to 17lbs.
I am going to start filling my tanks a full 20lbs. at my local ACE from now on. Also there was a little piece of paper folded up on my tank that said amerigas is being sued in a class action because of this practice. check out www.propanesettlement.com