Ok ... I can see the blends within the R134A, such as leak detector, oil, ... etc.
But if just using a 30lb bottle of R134, then it is pure with out the other additives used.
yes, the key word is controlling the amount of liquid and you are absolutely correct that it will take longer to refill/charge a 60 ton unit by gas. But this is solely for the experience HVAC Mechanic.
I remember this when I was loan to the HVAC shop in the early 1990s and the HVAC mechanics would charge a unit in liquid form verse gas.
But charging a car that requires 16oz of R134A or the mini van that required 56 ozs. Maybe it's not based on time constraint issues but to get the blends into the system ... correct.
Team Thunder Tiger
since 6/2005 to 12/2014