If you go by their feeding schedule, everything is in tsp, where as Big Bloom is listed on the bottle to use tbsp. Surprisingly didn't know about the FF feeding schedule until a month ago, the ladies are happy as can be though. Like the 'Pirate Code', it's more guidelines than rules.
Big Bloom can be used throughout the life cycle, it's Tiger Bloom that is flower focused. Although, I'm considering to continue using Grow Big until 2-3weeks into flower, tapering off as time goes, to continue to support the small veg growth that does still occur.