Agreeing with one of the previous posts, there might be a counting bug. I'll monitor it as a game I'm in progresses, but here is what I saw so far:

I had the boss for La Cosa Nostra, "Don Vichi"

At the beginning of the turn I also had the following Cosa Nostra (in addition to the boss):
1) Frankie ...

another thing, I'm 100% sure I had 6 latin kings, and still it says I had 4, thus giving me only a bonus of 1

I don't think the leader (el burro) counts, but other than him, you have five right? That's still a bug (it said 4 when you had 5 by my count): 1) Diablo 2) Tomas 3) Loco 4) Pollo 5 ...

Just an observation, have only played through three times (8 player games-- quads and standard singles). However with so many players, both times the map was won in the same way, and neither was due to the accumulation of gangs under their leaders.

The outside area behind the warden (Manuel, Dwayne ...