I can not understand why every tech in this trade does not completely check ever system worked on.
You will very quickly if the system is operating efficiently.
You check pressures and temps and find a Superheat at 2`F of 40`F
Or a subcooling at 1`F or 30`F
Of a T.D. at 30` or 7`F
How long does that take to measure??
You know at this point the system is not working at Max Efficiency.
At this point you start making money.
I feel it is a disservice to not get your customers system(s) at Max Efficiency