It's supposed to be tied to the time you turn your lights on (with their different color temp), not when you go to bed. But maybe some people use it differently?
It's not brightness, it is blue light. You are not suppose to turn blue off when it is time to go to bed. Blue light suppresses melatonin and it is important to start this early and not when your headed to bed.
Personally I hate artifical light and except for my kitchen my house is fairly dim. Work I just keep the lights off and have flu.x installed and dim my screen.
It also assumes you don't work in a well-light environment during the 3rd shift.
Regardless though, I think these shortcomings should be resolvable by simply setting your location in flux/redshift "incorrectly". So if you work the 3rd shift and use artificial lighting to give yourself an 'artificial day', then you'd just set flux/redshift to think that you are a continent or so over.
Not sure if you use flux, but you can set the colour temp for your daytime and your night time to match the kind of lights you are working under. They even mark certain temps like tungsten, fluoro, halogen etc ... So you don't have to assume anything.
I also use flux to match colour temperatures. It's pretty great!
