Well, this feature took me by surprise. That is, I hadn't worked with it on the Pre-production VW600ES I had here many months ago. (For all I recall, it may not even have been there at the time.) When this VPL-VW600 ES arrived, I had Mike go to work calibrating it immediately.
Once working with the projector and noticing it, I ran through the Pre-Check feature, but wasn't prepared to run the Auto Calibrate, until I knew more of what it would do to Mike's settings.
The manual was helpful. It describes the feature as a coarse setting, and compares and adjusts back to the original factory default, if I understand it correctly. There's even a comparison mode, pre vs. post. Thus, the assumption here, is that over time, the color (due to lamp aging in) will shift slightly, but the projector will adjust to take you back so it matches how the projector was, right out of the box in default.
That's great assuming the image is perfectly calibrated from the factory, but that isn't the case (although pretty good). I'd like to really explore the benefits of the feature over time, as the lamp shifts color slightly, but that won't be possible.
What would be an improvement (again, if I'm reading the info in the manual correctly, would be if it could instead match up against calibration settings put in when installed. In that case, your calibrator would deliver the best calibration, and in theory, every few hundred hours you could auto-calibrate and have it adjust for the lamp color shift. I'll make that a suggestion for Sony for the next generation projectors. Meatime, I will try the full auto-calibration and report back.