As you wrote in the other thread, the range of the backlight intensity may be limited by the UI. Your forthcoming app may be a long term solution one day. Anyway, currently it is still way too bright even with the lowest setting. By driving in the dark it annoys me more than it should.
Searching for a workaround, on one hand the screen with black screen apps is still too bright, and which I've seen were stupid too (didn't exit on touch). On the other hand the other, "off" functionality stops music playback, AA, and pretty much everything.
With the new skin (ah, "theme") I mentioned before, a big button comes with the proper dim functionality I'm looking for, and I'm fine with it basically. The only thing is that I can't control it by SWC. Something easy to live with.
Amongst the lines you answered my question at last: This kind of dim functionality is beyond control, can only be achieved by a hacky (custom software) way. Thank you for that!