I'm not an expert and do not pretend to be one of them. I recommend giving a little of nitrogen to young and older trees. I give nitrogen, I have enough of mangoes on my trees, taste is perfect compared to others. I give all the fertilizers, the main reason for the mango flowering is cold weather and enough nutrition. You don't believe me? I also listen what experts have to say and also want to see how they are doing. So, you can also go to the Fairchild Mango Farm at Fairchild Gardens and look at those (poorly enough to my eyes) looking trees with almost zero mangoes on trees grown by experts (I believe - zero nitrogen). My friend also gives fertilizers, Excalibur fertilizer, osmocote plus and seaweed fertilizer mix once a month every month and has a lot of fruits every year, he is also not an expert, he is pruning as I told him and gives fertilizer. I told him a few years ago to do that once in a spring time , but he continues doing the same every month, his trees are nothing to compare to the Fairchild mango farm trees - healthy looking (experts would say that this is a bad sign) and full of fruits during the season (Lemon Zest, Maha Chanok, Ugly Betty etc). He is possibly over-fertilizing mango trees as he grows bananas close to mangoes, gives the same fertilizer and has a lot of bananas like 20-50 bunches a year (dwarf namwah and Brazilian dwarf) from 200 sq ft banana grove. I had my first mango this year in March (Rosigold) and still have on trees (Keitt-not clean fruit and Providence -clean, no visible diseases). In my experience compost teas clear all the diseases, but I'm not perfect and also lazy. Others say compost teas do nothing. Now is time to listen what experts have to say.
If you don't want to give a nitrogen, just give a little of love.