moab and hydroplex first day of flower

My buddy is using M.O.A.B and hydroplex the first feeding of flipping the lights. I told him that is a little crazy. On the moab it says to use it at the begging of flower to help them flip. I still probably wouldn't personally. That's kinda a grip of pk at the time of flip. I wouldn't use either bloom booster that early and he is about to use both. What do you all think? Am I crazy or is that a good idea. I advised if he wants to do this he should at least choose one or the other....