While the position you posted is technically a D/P ATS, your methodology is incorrect.
Take the position below where he has 10 misses instead of 9:
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| XGID=--B---------------------a-:0:0:1:00:0:0:0:13:10 | |||||
| Blue on roll, cube action? | |||||
| Analyzed in Rollout | No double | Double/Take |
| Player Winning Chances: | 72.22% (G:0.00% B:0.00%) | 72.22% (G:0.00% B:0.00%) |
| Opponent Winning Chances: | 27.78% (G:0.00% B:0.00%) | 27.78% (G:0.00% B:0.00%) |
| Cubeless Equities | +0.444 | +0.900 |
| Cubeful Equities | ||
| No double: | +0.444 (-0.456) | ±0.000 (+0.444..+0.444) |
| Double/Take: | +0.900 | ±0.000 (+0.900..+0.900) |
| Double/Pass: | +1.000 (+0.100) | |
| Best Cube action: Double / Take | ||
| Rollout details | ||
| 1296 Games rolled with Variance Reduction. Moves: 3-ply, cube decisions: XG Roller | ||
| Double Decision confidence: | 100.0% | |
| Take Decision confidence: | 100.0% | |
| Duration: 0.2 second | ||
eXtreme Gammon Version: 2.10, MET: Kazaross XG2
This is a clear D/T at 13a - 13a. Using your methodology however, if we run this out over 8 games, the player on roll will win on average 11.5 and the opponent will win 4.5. Let's even round up the odd game over to the underdog in this position to give a 2a - 8a score at the end of 8 games of identical positions. The 8a player has 12.56% equity based on the match equity tables. So according to your thesis, he should drop this 8 times in a row and go to 5a - 13a and have 14% Match equity. Not as great as the difference in your example, but the same concept would still apply.