I bet 100 degrees and no humidity will get you to the lower end of the range, while 100 degrees and 100% humidity will get you to the top end of the range. Removing all that humidity from the air will take up a lot of the AC's cooling power.

 

Yeah, we don't get quite that hot, but we do get the humidity (I live 11 miles from Lake Huron). That's probably why mine is at the upper end of the scale.

 

So in my case, whats a reasonable ask of the shop? They told me already after I brought it to them that they saw 48 as the temp they got and everything was fine. My 96 kicks its but, the mid 30 degrees within a few minutes without a visor.

 

Really at this point you are at the mercy of the shop as the work they did was completed successfully unless there is still a leak somewhere. The only thing you could ask them to do is a vac and refill. If you're hitting 48 degrees we know the system is working. Maybe the they didn't put enough in or maybe they did but it doesn't hurt to check.

What temp was it outside when they tested the measurements? I'm wondering with the car that old and them changing all that they did why not change the condenser also. That would constitute a new system. Get yourself an infrared thermo and test the center vents on cycle at night. That way you know for sure what it's doing.