Do people agree that it is 'usually' correct to make the 23, rather than start the 22? And if so, why not here?
I don't know that this is true.
Here's a situation where you are more inclined to make the 23 point:
         
 
         
 | | White is Player 2
score: 3
pip: 131 | | 7 point match | pip: 180
score: 0
Blue is Player 1 |
|
| XGID=-a----CCB---bD---bee----BA:0:0:1:21:0:3:0:7:10 |
| Blue to play 21 |
| 1. | XG Roller++ | Bar/23 24/23 | eq: -0.4030 |
| Player:
Opponent: | 41.09% (G:8.13% B:0.30%)
58.91% (G:20.09% B:0.98%) | |
|
| 2. | XG Roller++ | Bar/22 | eq: -0.4132 (-0.0102) |
| Player:
Opponent: | 41.36% (G:7.79% B:0.29%)
58.64% (G:21.25% B:1.71%) | |
|
eXtreme Gammon Version: 2.10, MET: Kazaross XG2
Or here:
 
 
| | White is Player 2
score: 3
pip: 138 | | 7 point match | pip: 152
score: 0
Blue is Player 1 |
|
| XGID=-a-BB-BBB-A-bA--be-e----BA:0:0:1:21:0:3:0:7:10 |
| Blue to play 21 |
| 1. | XG Roller++ | Bar/23 10/9 | eq: +0.1303 |
| Player:
Opponent: | 51.43% (G:15.39% B:0.65%)
48.57% (G:14.71% B:1.14%) | |
|
| 2. | XG Roller++ | Bar/23 24/23 | eq: +0.1154 (-0.0149) |
| Player:
Opponent: | 51.03% (G:15.02% B:0.61%)
48.97% (G:13.55% B:0.75%) | |
|
| 3. | XG Roller++ | Bar/22 | eq: +0.0773 (-0.0531) |
| Player:
Opponent: | 50.30% (G:14.81% B:0.66%)
49.70% (G:14.82% B:1.12%) | |
|
eXtreme Gammon Version: 2.10, MET: Kazaross XG2