This seemed like a close decision to me. What puzzles me most, though, is that the rollouts below suggest that the difference between the top two plays is very different depending on whether it's a money game or whether it's 7a7a. Can this be right?

              
 
              
 | | White is Player 2
score: 0 pip: 154 | | 7 point match | pip: 125 score: 0
Blue is Player 1 | |
| XGID=aBa-CbD-B---B---aabbcbA--A:1:1:1:21:0:0:0:7:10 |
| Blue to play 21 |
| 1. | Rollout1 | Bar/24 4/2* | eq: +0.438 |
| Player: Opponent: | 51.82% (G:33.25% B:7.46%) 48.18% (G:14.90% B:1.16%) | Conf: ± 0.020 (+0.418...+0.458) Duration: 4 hours 08 minutes |
|
| 2. | Rollout1 | Bar/22 | eq: +0.338 (-0.100) |
| Player: Opponent: | 51.39% (G:24.85% B:5.44%) 48.61% (G:13.24% B:0.95%) | Conf: ± 0.020 (+0.318...+0.358) Duration: 3 hours 27 minutes |
|
| |
1 1296 Games rolled with Variance Reduction. Dice Seed: 2 Moves and cube decisions: 3 ply
|
eXtreme Gammon Version: 1.21, MET: Rockwell-Kazaross
For money:

              
 
              
 | | White is Player 2
score: 0 pip: 154 | Money session Jacoby | pip: 125 score: 0
Blue is Player 1 | |
| XGID=aBa-CbD-B---B---aabbcbA--A:1:1:1:21:0:0:1:0:10 |
| Blue to play 21 |
| 1. | Rollout1 | Bar/24 4/2* | eq: +0.385 |
| Player: Opponent: | 50.97% (G:30.37% B:1.60%) 49.03% (G:15.45% B:0.93%) | Conf: ± 0.012 (+0.373...+0.397) Duration: 6 hours 15 minutes |
|
| 2. | Rollout1 | Bar/22 | eq: +0.363 (-0.022) |
| Player: Opponent: | 51.44% (G:23.91% B:1.11%) 48.56% (G:13.66% B:0.63%) | Conf: ± 0.017 (+0.346...+0.380) Duration: 7 hours 36 minutes |
|
| |
1 2592 Games rolled with Variance Reduction. Dice Seed: 2 Moves and cube decisions: 3 ply
|
eXtreme Gammon Version: 1.21