I had a discussion recently w/ a tech. guy from a local supplier about charging new installs. We always weigh-in are charges (units comes w/ enough refrigerant for 15' of liquid line, over that ,add .6 oz. for every 1' of liquid line ) he liked the superheat/subcool methods. To me, weigh-ins are fool proof ( if ya got a accurate scale ), and faster. Why do s.h. or subcool when your startin fresh.any thoughts??