Czuch Chuckers: Well, it's just how the rollouts work.

with 3-2 the best move in a single point game (which is what the game in question is) is 24/21 13/11. This is not as bad as the best 4-1 (24/23 13/9) probably because the back checker is better situated on 21 and the checker on 9 can be hit more easily than on 11 where it is relatively safe and a good builder.

It's very marginal though, 3-2 isn't that good either.