I have 7 char and routinely wear +4 when i sell/buy, which is at least once per game day. So ok, assuming clothing bonus doesnt wear off too quick and those bonus cha settlers are more or less permanent, that still makes my max theoretically 21 settlers.
But i've had 23 settlers now in multiple settlements for a long, long time. Enough time they are de facto or actually are permanent.
The only correlation I've seen is that i appear to get a boost to max pop based on how high my happiness is.
Either way.,for my game, 10+cha even including clothing bonuses as permanent, is too low to account for my number of settlers.
Anyone else seeing more settlers in gheir game than what the presumed 10+cha formula implies?