There is no reason, other then experimenting and learning it doesn't work, to do anything but 12/12 for flowering. Same can be said about the nonsense of doing 48-72 hours of darkness at harvest.
All of these "tricks" have already been proven nonsense by myself and many others before me. 18/6 veg, 12/12 flower. Simple.
We did both reducing(bring 600 hps lights down to 300-400) and adding more light(switching 600s to 1000s) the last few weeks. We've done 48-72 hours of darkness. We've done different flowering and veg light schedules. We've done some other silly things as well just to try it, and none helped produce more bud or resin. As a matter of fact most experiments had negative results.