Been thinking and reading about this for a while now. IMO and trying to think like an outdoor plant, I believe boosting flower nutes P and K and reducing veg nute N (regardless of nutrient types used) when you see pre-flowers makes sense because you want the plant to think it’s got lots of goodies to eat when reduced light really kicks in flowering mode. That’s why FF nutes schedule shows gradual buildups and reductions of multiple nutes throughout the veg and flower periods. Just wish they had a better feed schedule for outdoor plants that grow for 5 months with flower mode after 12-16 weeks. Guess they can’t please all growers all the time.