The fertilizers with high middle numbers are generally thought to be designed for annuals to give them quick bloom boosts. With something like a flowering tree you need to be more concerned with the overall health. Therefore I recommend people stay away from high middle numbers.
I have for the past two years used Excalibur IX which is 11-11-13 with minors. It is especially formulated for Plumeria. I have seen a vast improvement in my plants. Note the number of blooming inflos on this Plumeria (picture taken last week)