James, in a previous post you said that HVAC-R isn't a science. I'd beg to differ. I have to know many things that can be considered scientific in nature. I have to know the properties of many materials and how they will react in a given situation. It is a part of our jobs to experiment with different chemicals, air flows, gasses, refrigerants, steam, controls, setpoints, temperatures, programs, timers, valves, flow controls, etc, to make the most efficient and/or best operating system we can manage with the tools and knowledge we have at hand. 8oz. of refrigerant can easily cost you 10% or better on your monthly electric bill.
Do you want the company that just adds enough refrigerant to make your system cool or do you want the person who will go about charging your system scientifically and thus having the most reliable, efficient, and stable system possible.
The bottom line is that those of us who have spent any amount of time (18+ years myself) learning and bettering ourselves in this field don't take condescending remarks any better than if I were to say the same about your chosen profession. What is it that you do for a living? Chances are that I can do it too.
...Ron -- 68'RS Camaro 88'Formula 00'GT Mustang