Everyone should be going by ppm N, P, K, etc. The label/brand doesnt mean shit. on the other hand No one shouild be going by the EC recomendations or "feed schedule" the company gives you. With Jacks "schedule" thats 200ppm N, which is what caused your crocodile leaves not because the label says Jacks on it. Try RO or 3-2-1 at EC 1 instead of EC2 like their schedule, that will be very close to old 6/9Head formula.
The maxibloom discontinued story comes around every 10 yrs for some reason, if it ever becomes a reality it can be diy'ed easily.