15-15-30 for budding?

I have been giving my plants 20-20-20 seeing amazing results until about august then switched too my 15-15-30 the plants are still healthy and growing good / budding (grow season ends late september early october where i live) But they are not budding 100% too what i thought they would be is this because there is still too much nitrogen or are they just going slow? and if too much nitrogen is cutting out the nutrients all together worth it because i will be loosing my p and k i need for flowering? plants are 6-7 ft tall atm

Get yourself some of this http://www.amazon.com/gp/aw/s//ref=mw_dp_a_s?ie=UTF8&k=Maxsea