Hi David - yes we have a long list of things to add to the client software. I regard the current efforts in the display industry as largely nonsense not founded in good science, and I will try to clarify why.
The main reason is that "ratio" is not a risk - instead, "dose" (total photons absorbed) is how risk is measured.
If you are concerned about hazard standards, you need a meter that can respond to extremely high light levels (usually as a spot meter), and currently the meters we recommend cannot do this. So for our research partners who are actually measuring hazard levels, we do not want to misrepresent our capabilities.
But what we are talking about here is the idea from people in the displays industry that levels 50x lower than the international standards may pose a risk, and simply put: there is no documented hazard at normal display radiance levels.
We can compute a hazard factor at lower light levels, but we do not think the TUV/etc. focus on this single number is appropriate, because it ignores overall radiance level. The retina is known to respond to total photons absorbed, not to a ratio, so without a measurement that corresponds to actual ICNIRP dose levels, we should not endorse a metric like this.
As for your worry that f.lux is not adequate: f.lux by default reduces the hazard factor by more than 90% (exceeding the levels of 10-20% that are being used in the market), so I would not worry about us in that regard. If there is a problem in these ranges, we are doing something to help, and I would submit that reducing this light by 10-20% does not do very much at all.
IEC62471 specifies that there is no BLH under 500 lux for large sources, so there is just not much to say about computer displays.
The candela is an SI unit, so even though it's an imperfect measure, everyone is going to use "lux" forever.
The metric you reference is "actinic power per lux" and gives you a relative measure of how much of the action spectrum is active at a certain intensity level. Many many people have "lux meters", and lights are often specified in terms of lux, so this gives a way to compare two lights at the same lux level.