Warmode phasing

Can anyone who understands the technical aspects of how the phasing implementation works, what decides which phase u will be placed in and how many horde/ally will be on that phase?

I’m on Mal’Ganis a historically high pop horde server and very very low pop ally server, yet everytime I’m out in the world doing any content there is a 99.9999999% Ally representation and If I see a horde its like finding a Spellshock Leggings socketed with 2 Zod runes and a Ber rune plus a billion gold from 1 murloc. I literally have yet to see a single horde this entire expansion, all I ever see is a billion ally. I’m just curious what exactly is going on here