Is the net weight of the recovery cylinder included in the total weight when filling a recovery cylinder? I know they should only be filled to 80% capacity ( 30lb cylinder should only be filled to 24lbs). But assuming when the cylinder is empty it's weight is 17 lbs, does that mean you can add 24lbs of freon to the cylinder making the total weight of the cylinder now 41 lbs. Or, does the 17 lbs net weight get included in the 24lb weight, meaning you can only add 7 lbs of freon to the 30lb cylinder?