Been meaning to do this for quite some time, so I bit the bullet today and did it. Really not difficult at all; wish I'd done it a long time ago! Anyway, for you seasoned pros, I have a question: I've identified the controls for blue drive, green drive, and blue cutoff, green cutoff, red cutoff. It appears they adjust the tints specified, but what's the difference between the "drive" controls and the "cutoff" controls? Any info appreciated.