I am very interested to read responses to your question as I'm also a fruit lover who is branching out now I'm in maintenance. I have some thoughts to share but I'm very new to maintaining so take them with a grain of salt. (I've been fiddling around with fruit since I hit 155, though, back in the summer!)
Mango is a pretty ambitious fruit to break away from berries with; isn't it one of the more sugary fruits out there? Did you try it with whipped cream, for the fat, or did you eat it on its own? Strangely, I can't eat any fruit on its own without seeing a water weight bounce. But if I eat the fruit in full fat yogurt, or with whipped cream or nut butter, it's generally okay. I can live with this.
Another thought: I probably have better luck when pairing fruit with fat because I don't eat as much. Generally, I have learned to loathe the idea of portion size; it's just not very helpful to us LCers, and thank goodness for that!
But I do find it useful with fruit. I've learned I can get away with eating a lot of almond butter and one very small (2.5 oz) apple a day, but when I switch to medium/grocery-store normal apple (5-6 oz), I do gain water weight. It drops off after a day at induction levels, but it's annoying!
I've made up my own fruit rungs, and am figuring out fruit-specific portions as I go. You wanna join my experiment?