Uh, no. The less you have the less the compressor can compress. Then more refrigerant stays gaseous and less cooling happens. Gaseous condition is already partially expanded and cannot cool like liquid refrigerant.
The evaporator freezes more than anything else by blower speeds falling lower, less air through evap then allows it to freeze easier. Why I eternally b-tch about the lack of super blowers to really push a/c performance up like on new cars.
The cooling amount depends on a certain density thing. You can get good cooling with slightly too little oil in system or too much but you won't hit the weight mark because the oil amount has to be dead on to hit the OEM refrigerant weight. I actually prefer slightly less oil in the systems, it allows for a slightly bigger load of refrigerant than normal but the density remains the same, it then freezes your butt off. I never add oil to any system and if lost you have to start all over.
I can get good cooling out of a system that is 20% low on refrigerant and it works great. Done it more than once. Why I never weigh anything at all, no need. And, you actually want to know if the oil amount is off, using true high pressure gauge setup indicates that instantly if you think.
