Its not in the manual but if you press the temp + and - buttons at the same time until the readout flashes in adjustment mode, you can calibrate what the actual inside temp is (using a thermometer) to what the digital readout says. It adjusts up and down in 2 degree increments.
Wait! WHAT!? Mine has consisently read about 5 degrees colder than it acutally is. I'm going to try this tonight...
AND...to answer the OP...I currently keep mine at 27-29F. seems to keep things cold, but not frozen. I did get some beer slushies at 27 for aday or two