The solid play like 13/11 6/5 is good when you're winning and need to tighten up your position before bringing it home. It also makes sense when you are losing badly and want to cut your losses. But it's just too passive early in the game when it's anybody game and you also have the security of an anchor. You have 9.5 checkers in the zone and a stacked 6pt; it't time to attack.
  White is Player 2
score: 0 pip: 146  Unlimited Game Jacoby Beaver  pip: 150 score: 0
Blue is Player 1  
XGID=aBEaBAdCbcbbB:0:0:1:21:0:0:3:0:10 
Blue to play 21 
1.  Rollout^{1}  8/7* 7/5  eq: 0.209 
 Player: Opponent:  43.77% (G:14.05% B:0.45%) 56.23% (G:14.24% B:0.65%)  Conf.: ± 0.014 (0.224...0.195)  [100.0%] Duration: 5 minutes 46 seconds 

2.  Rollout^{1}  13/11 6/5  eq: 0.250 (0.041) 
 Player: Opponent:  42.84% (G:10.74% B:0.31%) 57.16% (G:11.58% B:0.47%)  Conf.: ± 0.012 (0.262...0.238)  [0.0%] Duration: 6 minutes 22 seconds 


^{1} 1296 Games rolled with Variance Reduction. Dice Seed: 65637602 Moves: 3ply, cube decisions: XG Roller

eXtreme Gammon Version: 2.10
The following variants show that it's correct to hit no matter where your anchor is. Fight for the initiative in the early stages of the game!
  White is Player 2
score: 0 pip: 142  Unlimited Game Jacoby Beaver  pip: 146 score: 0
Blue is Player 1  
XGID=aBEaBAdCbcBbb:0:0:1:21:0:0:3:0:10 
Blue to play 21 
1.  Rollout^{1}  8/7* 7/5  eq: +0.289 
 Player: Opponent:  55.77% (G:17.09% B:0.43%) 44.23% (G:8.06% B:0.32%)  Conf.: ± 0.012 (+0.277...+0.301)  [100.0%] Duration: 5 minutes 55 seconds 

2.  Rollout^{1}  13/11 6/5  eq: +0.169 (0.120) 
 Player: Opponent:  53.66% (G:12.44% B:0.34%) 46.34% (G:6.82% B:0.26%)  Conf.: ± 0.012 (+0.157...+0.181)  [0.0%] Duration: 6 minutes 44 seconds 


^{1} 1296 Games rolled with Variance Reduction. Dice Seed: 19511397 Moves: 3ply, cube decisions: XG Roller

eXtreme Gammon Version: 2.10
  White is Player 2
score: 0 pip: 144  Unlimited Game Jacoby Beaver  pip: 148 score: 0
Blue is Player 1  
XGID=aBEaBAdCbcbBb:0:0:1:21:0:0:3:0:10 
Blue to play 21 
1.  Rollout^{1}  8/7* 7/5  eq: +0.094 
 Player: Opponent:  51.30% (G:15.74% B:0.43%) 48.70% (G:10.36% B:0.45%)  Conf.: ± 0.015 (+0.079...+0.108)  [100.0%] Duration: 6 minutes 18 seconds 

2.  Rollout^{1}  13/11 6/5  eq: +0.044 (0.050) 
 Player: Opponent:  50.10% (G:12.12% B:0.35%) 49.90% (G:8.69% B:0.34%)  Conf.: ± 0.011 (+0.033...+0.055)  [0.0%] Duration: 7 minutes 01 second 


^{1} 1296 Games rolled with Variance Reduction. Dice Seed: 19511397 Moves: 3ply, cube decisions: XG Roller

eXtreme Gammon Version: 2.10
  White is Player 2
score: 0 pip: 146  Unlimited Game Jacoby Beaver  pip: 152 score: 0
Blue is Player 1  
XGID=aBEaBAdCbcbbB:0:0:1:21:0:0:3:0:10 
Blue to play 21 
1.  Rollout^{1}  8/7* 7/5  eq: 0.485 
 Player: Opponent:  37.33% (G:12.78% B:0.44%) 62.67% (G:19.54% B:1.11%)  Conf.: ± 0.016 (0.501...0.469)  [100.0%] Duration: 4 minutes 41 seconds 

2.  Rollout^{1}  23/22 13/11  eq: 0.566 (0.081) 
 Player: Opponent:  36.83% (G:9.84% B:0.45%) 63.17% (G:21.58% B:1.00%)  Conf.: ± 0.019 (0.585...0.547)  [0.0%] Duration: 5 minutes 09 seconds 

3.  Rollout^{1}  13/11 6/5  eq: 0.573 (0.089) 
 Player: Opponent:  35.53% (G:9.86% B:0.33%) 64.47% (G:17.18% B:0.88%)  Conf.: ± 0.014 (0.587...0.559)  [0.0%] Duration: 4 minutes 55 seconds 


^{1} 1296 Games rolled with Variance Reduction. Dice Seed: 19511397 Moves: 3ply, cube decisions: XG Roller

eXtreme Gammon Version: 2.10
  White is Player 2
score: 0 pip: 146  Unlimited Game Jacoby Beaver  pip: 154 score: 0
Blue is Player 1  
XGID=aBEaBAdCbcbbB:0:0:1:21:0:0:3:0:10 
Blue to play 21 
1.  Rollout^{1}  8/7* 7/5  eq: 0.484 
 Player: Opponent:  38.11% (G:13.01% B:0.56%) 61.89% (G:22.25% B:1.61%)  Conf.: ± 0.018 (0.502...0.466)  [100.0%] Duration: 5 minutes 07 seconds 

2.  Rollout^{1}  13/11 6/5  eq: 0.603 (0.119) 
 Player: Opponent:  35.66% (G:10.44% B:0.39%) 64.34% (G:20.40% B:1.15%)  Conf.: ± 0.014 (0.617...0.589)  [0.0%] Duration: 4 minutes 47 seconds 


^{1} 1296 Games rolled with Variance Reduction. Dice Seed: 19511397 Moves: 3ply, cube decisions: XG Roller

eXtreme Gammon Version: 2.10