I've been using fox farm hydro nutes originally for some time now with good results, but being scienticly minded I wanted to really understand what the nutrients and supplements we're actually doing so I've been doing a lot of studying this year, scientific articles etc......nutrients and nutrient companies get brought up all the time on these forums so I was really motivated to seperate the bs marketing from horticultural science. I read a lot if people saying "plants don't care what nutrients you give them" or statements to that effect. I will pay more for higher quality nutrients, use the right nutrient FORM for the specific stage of life the plant is in, utilize biostimulants and natural chelates for better nutrient uptake. That's part of the reason I wanted to change up my nutrient regamine and give RX a try. I could buy bulk soluble powders at this point and custom mix my feedings but I also appreciate the convienance factor of two part bottles
To answer your question I'm not sure why the dosage increases in their schedule, from what I understand a little bit if nutrient stress in the flowering stage helps encourage antioxidant production and essential oils where nitrogen toxicity in veg stage can actually prevent flower production. The CEO of rx had told me their nutrients have a low salt content so it would be harder to burn the plants