are there any toxicity symptoms? If not, then the plant probably needs it still.
despite a widely held belief that the plants all of a sudden don't require N in bloom is an unproven in any meaningful way.. like people's obstinate belief that flushing reduces mineral content in buds... ppl used to say that with striking confidence and it's totally wrong. I'd bet money this will be yet another urban myth proven false with only a modicum of reputable research.
If the leaves start getting dark green and other issues related to a toxicity, that means the plant is no longer using it at the same rate and you should dial back N in you rmix...
if this never happens, then it is clearly still using the N and you should still be providing it at a similar concentration/rate.
N is used in cellular growth...whether stems or buds. it's part of DNA / RNA, numerous other cellular parts, hormones, et al... is there a proportional difference? maybe... but if it never shows a toxicity it is using the damn molecule, lol. it's an assumption made be a mob of people that have never taken a single biology or chemistry class. if proven through study or you see the plant reacting as discussed, then you can put a little more faith into it.
in my experience, i rarely have to dial back from 120-130ppm N. Rarely, there is a strain that will want a bit less or i'll get a minor amount of clawing and dark foliage with weak stems -- all symptoms of an N-tox. "That" plant wanted a little less N and it was probably true long before bloom phase, too.
What i don't have is a burnt up, quickly deteriorating, necrotic canopy of dead leaves that can't photosynthesize after just 6-7 weeks of bloom, lol. Senescence is sometimes inevitable, but what i see from "bloom" formulas as instructed by these 'marijuana-branded' fertilizer companies often leads to a fucked up plant. if it has a child-like cartoon graphic on the front, you should assume they aren't professional products, LOL... at the least it is a high correlation.