That stuff can be pretty powerful from what I understand. I would try to follow directions as far as when to use, but go easy on the dosage until you know how your plants react. Some just give a nice dose for the first week of flowering and then wait until the last 3 to 4 weeks to use again on flower boosters. Me, I only use the last few weeks. Also, I would not give it with any other main nutes, meaning cut out your other main NPK stuff, but you can probably still use any additives such as Liquid Karma, CalMag, and things like this and if you are using SuperThrive you want to stop using it in flower unless the plant is stressed and that go's for most vit B additives IMO.
Like I said, be careful with the first dose. Couple weeks back my wife gave a plant that was still in the first week of flower a mix that was for some older girls which contained a very small amount of Cool Bloom and it burnt the heck out of the plant, gave her leaf burn and some canoe leaves, so be careful.
Adieu