I also do not run the AC or use defrost setting as this turns on the compressor even if it's set to 90 degrees.
I only use it if I need to melt Ice off the windshield or I can't take the heat any longer setting in traffic.
Stock fan settings turn on at 211-214 and turn off at 204-207
This supposedly gives the best fuel emissions.
When a AC is on, one fan will always run and increase speed and/or turn both on as needed.
I have my tuner set my fans to turn on at 175 with a 175 thermostat for max HP but running colder also deceases MPG by .5 to 1
Having said all that, sometimes a fresh flash back to stock and back to tune and a battery disconnect, will most likely solve the little hiccups.