Take a look at this video from Utah State University. At 10:30 mins they show data that shows NO INCREASE in yield or THC/CBD if using 100 ppm phosphorus over 25 ppm P. So 25-50 ppm is all that one would ever need if at all. There is just no benefit in using more. Consider that some even push P as high as 200 or even higher that's almost 10 fold. That is by far not needed, it is just a waste and could even be detrimental by antagonizing/Interfering with calcium etc. So P "boosters" are indeed just a marketing invention, there even is no need for a special flowering formula. The industry wants people to believe it is but real scientific research shows it is not.