I noticed that the Auto fan control reverts back to default instead of using Precision's fan control curve when turning the Auto button off or on and clicking Apply.

What I would do is not even touch the Auto button..I would (and do) create my own different custom fan curves and settings and assign them to a profile number..Then I just click on the profile number, then Load..If you do touch it, just realize what will happen.

Any time you find the 'Fan Curve Control' box not lighted, the fan control has reverted back to the defaults of using the card's fan control..Any time the Auto button is not lighted, the fan speed is fixed and won't increase/decrease.

It does take a little messing around to figure out how Precision works..Best thing to do is use profiles..Make sure you're using the latest version of Precision (1.0.6) too.