hey man, i looked at that chart, same one i lost months ago.

here's my thinkin, FWIW

gotta go by the Nute levels. N-P-K

Grow Big (says right on bottle "for lush vegetative growth") and is 6-4-4 (strong N for veg)

Big Bloom is 0.01-0.3-0.7 and u do use more of this per dose than the Grow Big. (nearly no N)

thats my story and im stickin to it.