That is funny on the book!!
Bloom booster is really designed for annuals, to give them a quick kick to make them grow fast and bloom a lot. It will not do anything to promote the health of a plant you want to keep around for a while.
Much better for Plumeria is a balanced, timed-release fertilizer such as Dynamite 13-13-13, and in the spring and throughout the growing season supplement with organic stuff such as horse manure, seaweed, bone meal etc. You're not looking for a quick bloom cycle, you're looking to make this grow into a strong healthy tree which will bloom reliably.
Like this
