theres a game mechanic that reduces polo volume when more are added, this is most noticeable with voice 4 in dystopia, and melody 5 in xrun. clearly this hasnt been done on the mod, hopefully it will change, it sounds like a loud mess
Modding, also the reason why there is only 3 polos in the voices is because 2 of them are unfinished and have a creepy look and have basic alpha sounds