Whats the most efficient way of using the A/C? Do I leave it on Auto at a temp like 75, or what I currently do which is leave the setting at 65 and manually cycle on-off the a/c compressor...kinda a pain as its a few button presses to get to the climate screen.

Is the a/c compressor is always on in the Auto mode, thus reducing MPG? Or is the system smart and auto cycle the compressor based on the temp setting?

The compressor shuts off and on and and fans adjust based on the temperature (and what its like outside) that you have it sitting at.

The most efficient use is off and an Ice bucket in the window......