Stacked camera sensors have been a thing for a while now; they have improved sensitivity to light by stacking translucent photodiodes on top of each other.
The Nichia 719A is the inverse; translucent LEDs are stacked on top of each other (in a single package) for increased intensity.
Yeah it’s probably not likely you will get one that is to either of the extremes of the flux range, but technically it’s possible. It makes sense considering they are stacking 2 dies. So each die on its own has a ±5% flux? I’m really interested in knowing how they make these and how exactly they work. Like does one die have more impact than the other die? If the bottom die has low flux is that better or worse than the top having low flux? Lots of questions in my mind about these things.