Tank size has not changed, but be aware that Amerigas was only filling a 20lb'er with 15 lbs of fuel. They got called out on it a few years ago and they came up with "we wanted to keep the prices the same for our customers despite the rising price of propane", 20lb propane tanks are supposed to be filled to 17lbs for safety reasons, both Amerigas and Bluerino were shorting everyone, meanwhile the price of propane has dropped and both companies continue to fill with only 15lbs..