That's what I thought but, I have settlements one with 80 people with only 3 huts ( 3 x 25 = 75) and another with 90 pepole and only 3 huts (3 x 25 = 75)?
Even without huts, you have a max pop of 10... so add 3x25 (75) to that, is 85 cap.... Also, there is a 'housing' type tech, that actually increases all pop cap by 10% total (not sure if once, or each time).. So.. 10% of 85 is 8.5.. round up to 9 (or down to 8, either way).. and that's 93/94 ..