why are nutrients always designed to be to strong

just something i was pondering. like i have some Canadian express coco grow and bloom and they recommend a cf of 16-24. but that's insane. i would go 12 at most. any higher and i get nute burn. i usually go at about 7-8 and that's with 3 foot plants. and this seems to be the case with all nutrients. it's even written down on all the guides to feed about quarter or half of the recommended does. so why do these companies make the dosing so ridiculously high. i mean they're making the product and they must have tested it many times so what was so different about their circumstance or growing conditions that led to such high estimations. a lot of these companies design nutrients just for marijuana and a lot of them test them on marijuana so like what's up?

chur

a lot of companies want you to use a high ppm so you'll use it up, and buy more. doesn't make much sense, if you ask me. i don't even read what they suggest. i grow in coco, and seldom use a ppm higher than 8-900. i slowly increase the ppm till i see tip burn. that tells me i'm a hundred or two ppm too high. you can back it down a bit or leave it there. i don't mind a bit of tip burn, and leave it where it's at. each strain has a level/ppm that it likes.