Looks like it does.id just switch off the auto adjust + use the slider in notification area. does Lux have its own auto adjust?
When I downloaded and installed it, I tapped the Auto icon and the brightness levels were automatically adjusted and displayed in percentage and lx.
I checked the display settings and noted that the "Auto brightness" box was unchecked after installed Lux.
Just took the dog for a walk on a creek trail where the S III normally is dimmed lower than I would want it to be. It made the screen brighter than it normally would be.
After returning home, the brightness automatically decreased via Lux where I don't have much lighting turned on.
This may be the answer I was looking for to replace the built-in Automatic brightness.