The tree leaves looks dark green to me. I wouldn't give any fertilizer anymore this year.
Depending on the weather it could flush late and not have flowers next year on the new growth.
I have a couple larger mango trees and I don't fertilize them at all. I do give my young mangos
8-4-8. My neighbor gave his large Lancetilla and Angie fertilizer non stop last year and the leaves
are super dark green and not one flower this year.