diff --git a/docs/experiment_round40_waste0.1.json b/docs/experiment_round40_waste0.1.json
new file mode 100644
index 0000000..dfd6403
--- /dev/null
+++ b/docs/experiment_round40_waste0.1.json
@@ -0,0 +1,82 @@
+{
+  "config": {
+    "ckpt": "ml/runs/base_dag2_dag1/best.pt",
+    "samples": "ml/data/samples",
+    "tasks": null,
+    "split": "val",
+    "n": 256,
+    "K": 8,
+    "commit": 2,
+    "fb": 2.2,
+    "ki": 0.0,
+    "fb_scale": 0.0,
+    "fb_near": 0.2,
+    "fb_fallback": 0.0,
+    "kdecay": 0.9,
+    "kimax": 0.5,
+    "fb_every": 1,
+    "safety_try": 0,
+    "sel_w": 0.1,
+    "dls_safety": 1,
+    "fb_clear": 0.0,
+    "fb_cmin": 0.3,
+    "sub_refresh": 0,
+    "fb_block_gain": 0.5,
+    "dump": null,
+    "out": "docs/experiment_round40_waste0.1.json",
+    "trace": null,
+    "select": "ep_waste",
+    "replan": "empty",
+    "safety": 1,
+    "partial": 1,
+    "inc_cap": 1,
+    "gap_margin": 0.0,
+    "cert_batch": 0,
+    "steps": 1,
+    "z_scale": 1.0,
+    "len_w": 0.1,
+    "backoff": 0,
+    "max_sec": null,
+    "seed": 0,
+    "dls": "analytic",
+    "device": "cuda"
+  },
+  "batch_size": 256,
+  "batch_seed_rule": "same seed per batch",
+  "checkpoint_sha256": "f7f686fd8ee92fb6948fbcc4ee954636065ad87bb54f661c4f8f575bc16c2ce1",
+  "tasks_sha256": "249bd93457825cda98c59e64d9a096d3473c69aeb3553de1dea6d9e56be71772",
+  "kin_fp": "2ebcbf17",
+  "act_scale": 1.0,
+  "metrics": {
+    "n": 256,
+    "n_ref": 256,
+    "success": 0.515625,
+    "collision_free_success": 0.515625,
+    "time_ok_1p3": 0.26953125,
+    "collision_rate": 0.0,
+    "collision_steps_mean": 0.0,
+    "travel_ratio_median": 2.669708251953125,
+    "time_mean_s": 2.452272653579712,
+    "brakes_mean": 19.39453125,
+    "start_fail": 0.0,
+    "goal_ratio_2s": 0.28827616572380066,
+    "err_fail_med": 201.7505645751953,
+    "err_success_med": 0.20423255860805511,
+    "dls_share": 0.609375,
+    "time_budget": "teacher×2(≥3 s)",
+    "speed_ratio_p50": 1.0000016689300537,
+    "speed_ratio_p95": 1.0000101327896118,
+    "speed_ratio_max": 1.0000101327896118,
+    "over_vmax_rate": 0.0,
+    "accel_ratio_p95": 1.0000016689300537,
+    "accel_ratio_max": 1.0000101327896118,
+    "reverse_p50": 0.2527472674846649,
+    "reverse_mean": 0.262615442276001,
+    "reverse_moving_p50": 0.31912145018577576,
+    "moving_share_p50": 0.9599999785423279,
+    "brake_rate_mean": 0.09945914149284363,
+    "brake_rate_p50": 0.0051282052882015705,
+    "n_plans_mean": 195.0
+  },
+  "simulation_wall_s": 308.12369770000805
+}
diff --git a/docs/experiment_round40_waste0.3.json b/docs/experiment_round40_waste0.3.json
new file mode 100644
index 0000000..e15d828
--- /dev/null
+++ b/docs/experiment_round40_waste0.3.json
@@ -0,0 +1,82 @@
+{
+  "config": {
+    "ckpt": "ml/runs/base_dag2_dag1/best.pt",
+    "samples": "ml/data/samples",
+    "tasks": null,
+    "split": "val",
+    "n": 256,
+    "K": 8,
+    "commit": 2,
+    "fb": 2.2,
+    "ki": 0.0,
+    "fb_scale": 0.0,
+    "fb_near": 0.2,
+    "fb_fallback": 0.0,
+    "kdecay": 0.9,
+    "kimax": 0.5,
+    "fb_every": 1,
+    "safety_try": 0,
+    "sel_w": 0.1,
+    "dls_safety": 1,
+    "fb_clear": 0.0,
+    "fb_cmin": 0.3,
+    "sub_refresh": 0,
+    "fb_block_gain": 0.5,
+    "dump": null,
+    "out": "docs/experiment_round40_waste0.3.json",
+    "trace": null,
+    "select": "ep_waste",
+    "replan": "empty",
+    "safety": 1,
+    "partial": 1,
+    "inc_cap": 1,
+    "gap_margin": 0.0,
+    "cert_batch": 0,
+    "steps": 1,
+    "z_scale": 1.0,
+    "len_w": 0.3,
+    "backoff": 0,
+    "max_sec": null,
+    "seed": 0,
+    "dls": "analytic",
+    "device": "cuda"
+  },
+  "batch_size": 256,
+  "batch_seed_rule": "same seed per batch",
+  "checkpoint_sha256": "f7f686fd8ee92fb6948fbcc4ee954636065ad87bb54f661c4f8f575bc16c2ce1",
+  "tasks_sha256": "249bd93457825cda98c59e64d9a096d3473c69aeb3553de1dea6d9e56be71772",
+  "kin_fp": "2ebcbf17",
+  "act_scale": 1.0,
+  "metrics": {
+    "n": 256,
+    "n_ref": 256,
+    "success": 0.515625,
+    "collision_free_success": 0.515625,
+    "time_ok_1p3": 0.265625,
+    "collision_rate": 0.0,
+    "collision_steps_mean": 0.0,
+    "travel_ratio_median": 2.5349059104919434,
+    "time_mean_s": 2.476060628890991,
+    "brakes_mean": 19.62890625,
+    "start_fail": 0.0,
+    "goal_ratio_2s": 0.31392601132392883,
+    "err_fail_med": 200.5723876953125,
+    "err_success_med": 0.16847863793373108,
+    "dls_share": 0.609375,
+    "time_budget": "teacher×2(≥3 s)",
+    "speed_ratio_p50": 1.0000016689300537,
+    "speed_ratio_p95": 1.0000101327896118,
+    "speed_ratio_max": 1.0000101327896118,
+    "over_vmax_rate": 0.0,
+    "accel_ratio_p95": 1.0000016689300537,
+    "accel_ratio_max": 1.0000101327896118,
+    "reverse_p50": 0.25111111998558044,
+    "reverse_mean": 0.26184794306755066,
+    "reverse_moving_p50": 0.3268229067325592,
+    "moving_share_p50": 0.9636363387107849,
+    "brake_rate_mean": 0.10066106170415878,
+    "brake_rate_p50": 0.0051282052882015705,
+    "n_plans_mean": 195.0
+  },
+  "simulation_wall_s": 299.3823047999904
+}
diff --git a/docs/experiment_round40_waste1.0.json b/docs/experiment_round40_waste1.0.json
new file mode 100644
index 0000000..508c642
--- /dev/null
+++ b/docs/experiment_round40_waste1.0.json
@@ -0,0 +1,82 @@
+{
+  "config": {
+    "ckpt": "ml/runs/base_dag2_dag1/best.pt",
+    "samples": "ml/data/samples",
+    "tasks": null,
+    "split": "val",
+    "n": 256,
+    "K": 8,
+    "commit": 2,
+    "fb": 2.2,
+    "ki": 0.0,
+    "fb_scale": 0.0,
+    "fb_near": 0.2,
+    "fb_fallback": 0.0,
+    "kdecay": 0.9,
+    "kimax": 0.5,
+    "fb_every": 1,
+    "safety_try": 0,
+    "sel_w": 0.1,
+    "dls_safety": 1,
+    "fb_clear": 0.0,
+    "fb_cmin": 0.3,
+    "sub_refresh": 0,
+    "fb_block_gain": 0.5,
+    "dump": null,
+    "out": "docs/experiment_round40_waste1.0.json",
+    "trace": null,
+    "select": "ep_waste",
+    "replan": "empty",
+    "safety": 1,
+    "partial": 1,
+    "inc_cap": 1,
+    "gap_margin": 0.0,
+    "cert_batch": 0,
+    "steps": 1,
+    "z_scale": 1.0,
+    "len_w": 1.0,
+    "backoff": 0,
+    "max_sec": null,
+    "seed": 0,
+    "dls": "analytic",
+    "device": "cuda"
+  },
+  "batch_size": 256,
+  "batch_seed_rule": "same seed per batch",
+  "checkpoint_sha256": "f7f686fd8ee92fb6948fbcc4ee954636065ad87bb54f661c4f8f575bc16c2ce1",
+  "tasks_sha256": "249bd93457825cda98c59e64d9a096d3473c69aeb3553de1dea6d9e56be71772",
+  "kin_fp": "2ebcbf17",
+  "act_scale": 1.0,
+  "metrics": {
+    "n": 256,
+    "n_ref": 256,
+    "success": 0.48828125,
+    "collision_free_success": 0.48828125,
+    "time_ok_1p3": 0.23828125,
+    "collision_rate": 0.0,
+    "collision_steps_mean": 0.0,
+    "travel_ratio_median": 2.708263874053955,
+    "time_mean_s": 2.5168001651763916,
+    "brakes_mean": 20.02734375,
+    "start_fail": 0.0,
+    "goal_ratio_2s": 0.3584502637386322,
+    "err_fail_med": 190.41900634765625,
+    "err_success_med": 0.33570292592048645,
+    "dls_share": 0.60546875,
+    "time_budget": "teacher×2(≥3 s)",
+    "speed_ratio_p50": 1.0000016689300537,
+    "speed_ratio_p95": 1.0000101327896118,
+    "speed_ratio_max": 1.0000101327896118,
+    "over_vmax_rate": 0.0,
+    "accel_ratio_p95": 1.0000016689300537,
+    "accel_ratio_max": 1.0000101327896118,
+    "reverse_p50": 0.24899598956108093,
+    "reverse_mean": 0.2592279314994812,
+    "reverse_moving_p50": 0.3214285671710968,
+    "moving_share_p50": 0.9587156176567078,
+    "brake_rate_mean": 0.10270433127880096,
+    "brake_rate_p50": 0.010256410576403141,
+    "n_plans_mean": 195.0
+  },
+  "simulation_wall_s": 297.2535624000011
+}
diff --git a/docs/探索日志.md b/docs/探索日志.md
index 917277f..a1dbc76 100644
--- a/docs/探索日志.md
+++ b/docs/探索日志.md
@@ -141,6 +141,23 @@
 - 与失败分类完全对上：63/109"走一半被冻住"就是这批题；**它们同时也是到达缺口的全部来源**（可拿的 +25 pp 区间就在这批题里）。所以攻它们不是锦上添花，是主攻方向。
 - 待办（等链跑完再改库，避免重犯 14:45 那次事故）：给 `eval_cl` 补 `brake_rate_p90` 与 `stuck_share`（判据 `brake_rate > 0.2` 的题占比）。
 
+## `ep_waste` 三臂也是负结论，但给出了原因：罚的是没被执行的那段地平线（轮次 42）
+
+- 同一 256 题同 seed、`--inc_cap 1`，只改 `select=ep_waste --len_w`（罚 `1 − 同轴净/总` × 当前误差）：
+
+  | 臂 | 到达 | 时限内 | 行程比 | 刹车/题 | 刹停率 mean / p50 | 换向率 |
+  |---|---|---|---|---|---|---|
+  | 对照（endpoint，1 步限幅） | 0.5234 | 0.2656 | 2.6158 | 19.55 | ≈0.099 / — | 离线 0.247 |
+  | waste 0.1 | 0.5156 | 0.2695 | 2.6697 | 19.39 | 0.0995 / 0.005 | 0.2527 |
+  | waste 0.3 | 0.5156 | 0.2656 | **2.5349** | 19.63 | 0.1007 / 0.005 | 0.2511 |
+  | waste 1.0 | **0.4883** | **0.2383** | 2.7083 | 20.03 | 0.1027 / 0.010 | 0.2490 |
+
+  （`docs/experiment_round40_waste{0.1,0.3,1.0}.json`）
+- **行程比没有随权重单调下降**（2.67 → 2.53 → 2.71 vs 对照 2.62）：0.3 那一格看着像改善，但两侧都比它差 ⇒ 不是趋势，不能拿单点报"行程降了 0.08"。权重加到 1.0 时到达 −3.5 pp、时限 −2.7 pp，纯亏。
+- **原因（这条比结论更有用）**：打分用的浪费比例是在**候选的 16 步地平线**上算的，而每拍真正提交只有 `commit_n=2` 步。排序被"后面 14 步会不会来回抖"牵着走，执行的前 2 步基本不变 ⇒ 改了顺序改不了行为。**要影响执行，惩罚必须只算在会被提交的那段前缀上。**
+- 与 `ep_len` 三臂合起来看：**选择期的"路径形状类"惩罚（总行程 / 浪费比例）在两个版本上都是负结论**，而选择期的"多给活路"（K=16 +3.9 pp）和"几何信息进打分"（#24，待测）才是对的方向。差别在于前者动的是没被执行的那段，后者动的是被拒/被选的那 2 步。
+- 内部一致性：`brake_rate_mean` 0.0995/0.1007/0.1027 与 `brakes_mean/n_plans` = 19.4/195 ≈ 0.0995 逐位对得上 ⇒ 刚补的分母口径没接错。
+
 ## K=16 串行 vs 批量认证等价 + 第一次真正核算"刹停率"（轮次 41）
 
 - `--K 16 --cert_batch 1` 与 `--K 16`（串行）跑同一 256 题同 seed：`success / time_ok_1p3 / brakes_mean / travel_ratio_median / collision_*` **全部逐位相同**，差异键只有 7 个、且全是我这几轮新加/改口径的报表键（`reverse_*` 的两种口径、`n_plans`、`brake_rate`、`moving_share`）。⇒ **轮次 39 的"试候选数 1/3/8/16 曲线"同样描述批量口径**，也就是说 K=16 到达 0.5625 这个收益不依赖串行早停这个巧合。