It's been around for a few years. Since PAR meters got more affordable. I'm not sure the science is settled. My understanding is that if you're using typical PAR levels and the common 18/6 + 12/12 cycles, you're already in the zone.
Another theory worth reading up on, is that the dark hours are important for terpene production. Again, like all things cannabis, there are varying opinions here. But I do know my own plants are more aromatic later in the dark cycle and first thing during lights on. This data just comes from my nose! Consequently, I don't let my lights turn on for 18-24hrs just before harvest. Try sniffing your plants at different times of day, its fun!