I was traveling through Maine recently and saw a sign for $11 tank refill. A very nice lady came out and filled my tank to its maximum weight. The tank actually had 20 pounds of propane in it when she was done. She said that during the summer, she fills 10 to 20 tanks a day. She said that they price their refills to be about equal to what they charge for delivered lp only they don't have to deliver it. Most people have partial tanks that they want topped off, it still cost $11. She fills it to the full weight.
Ok, now let someone come on and tell us that a full tank is only 80% capacity, and then claim that 16 pounds is full. Please do some research. These tanks have a 100% volume of 25 pounds.