diff --git a/B03_FileInput/B03_FileInput_Service_Chain.py b/B03_FileInput/B03_FileInput_Service_Chain.py
index e51abe468..c5fac8502 100644
--- a/B03_FileInput/B03_FileInput_Service_Chain.py
+++ b/B03_FileInput/B03_FileInput_Service_Chain.py
@@ -390,7 +390,6 @@ async def run_preprocess_chain(
         mark_designing,
         read_design_failure,
     )
-    from common_util.common_util_route_geometry import expected_route_csv_path
     from common_util.common_util_storage import resolve_stored_project_path
     from common_util.common_util_surface_confirmation import (
         design_terrain,
@@ -416,9 +415,9 @@ async def run_preprocess_chain(
             missing = "sheet" if design == "las" else "las"
             sets.note_unbuilt(root, missing, f"{missing} 지표면 모델 없음 — 한 벌만")
         else:
-            # 예상노선(공유)은 설계 지형 벌이 씀 — 다른 지형으로 자른 것이 남지 않게
-            expected = expected_route_csv_path(root)
-            had_expected = expected.is_file()
+            # 예상노선(공유 · 추천이 씀)은 설계 지형으로 자른 것 하나 — 먼저 적어 두면 두 벌이 같은
+            # 평면 노선으로 지어짐(지형만 다름 · 다른 지형 벌 [초기화]도 같은 노선)
+            await _seed_expected_route(project_id, root, params)
             try:
                 async with pool.acquire() as connection:
                     model_id = await sets.switch_terrain(connection, project_id, other)
@@ -438,8 +437,6 @@ async def run_preprocess_chain(
                     await sets.clear_active_set(connection, root, str(project_id))
                 sets.note_unbuilt(root, other, f"짓기 오류: {exc}")
             finally:
-                if not had_expected:
-                    expected.unlink(missing_ok=True)
                 async with pool.acquire() as connection:
                     await sets.switch_terrain(connection, project_id, design)
             marks.append((f"{other} 벌", time.perf_counter()))
@@ -456,6 +453,26 @@ async def run_preprocess_chain(
         schedule_precompute(project_id)  # 추천은 지형 · 예정노선만 씀 — 실패 길에도(763-3)
 
 
+async def _seed_expected_route(project_id: UUID, root: Path, surface: dict[str, Any]) -> None:
+    """예상노선 정본을 설계 지형으로 잘라 적음(없을 때만 · 자동 체인 2.5 와 같은 값)."""
+    from common_util.common_util_route_geometry import expected_route_csv_path, write_route_csv
+    from config.config_db import get_db_pool
+
+    path = expected_route_csv_path(root)
+    if path.is_file():
+        return
+    async with get_db_pool().acquire() as connection, connection.cursor() as cursor:
+        await cursor.execute(
+            "SELECT route_start_m, route_end_m FROM projects WHERE id = %s", (str(project_id),)
+        )
+        row = await cursor.fetchone()
+    points = await asyncio.to_thread(
+        _planned_route_points_in_project_crs, root, surface, (row[0], row[1]) if row else None
+    )
+    if points:
+        write_route_csv(path, points)
+
+
 async def _ensure_initial_polyline(
     project_id: UUID, project_root: Path, points: list[dict[str, float]]
 ) -> None:
diff --git a/resources/tester/test_765_design_sets.py b/resources/tester/test_765_design_sets.py
index fa91eda29..2948283c2 100644
--- a/resources/tester/test_765_design_sets.py
+++ b/resources/tester/test_765_design_sets.py
@@ -428,9 +428,11 @@ def _chain_world(monkeypatch, tmp_path: Path, *, other, built_other=True):
 
     async def auto(pid, model_id=None, inner=False):
         log.append(("auto", model_id, inner))
-        expected.parent.mkdir(parents=True, exist_ok=True)
-        expected.write_text(str(model_id), encoding="utf-8")  # 체인이 처음 쓰는 예상노선
-        return {"route_id": 1} if (built_other or len(log) > 2) else None
+        if not expected.is_file():  # 체인 2.5 — 없을 때만 그 지형으로 자른 예상노선
+            expected.parent.mkdir(parents=True, exist_ok=True)
+            expected.write_text(str(model_id), encoding="utf-8")
+        first = sum(1 for item in log if item[0] == "auto") == 1
+        return {"route_id": 1} if (built_other or not first) else None
 
     async def switch(_c, _pid, terrain):
         log.append(("switch", terrain))
@@ -459,7 +461,14 @@ def _chain_world(monkeypatch, tmp_path: Path, *, other, built_other=True):
     monkeypatch.setattr(sets, "park_active_set", park)
     monkeypatch.setattr(sets, "clear_active_set", clear)
     monkeypatch.setattr(sets, "set_fingerprint", fingerprint)
+
+    async def seed(_pid, _root, surface):
+        log.append(("seed", surface["source_filter"]))
+        expected.parent.mkdir(parents=True, exist_ok=True)
+        expected.write_text("design", encoding="utf-8")
+
     monkeypatch.setattr(chain, "run_auto_design_chain", auto)
+    monkeypatch.setattr(chain, "_seed_expected_route", seed)
     monkeypatch.setattr(router, "schedule_precompute", lambda pid: log.append("precompute"))
     return chain, log, expected
 
@@ -474,6 +483,7 @@ def test_전처리_체인_다른_지형_먼저_떠_두고_설계_지형(monkeypa
     summary = asyncio.run(chain.run_preprocess_chain(PID, 5))  # type: ignore[arg-type]
     assert summary == {"route_id": 1}
     assert log == [
+        ("seed", "classification"),  # 예상노선 = 설계 지형으로 먼저
         ("switch", "sheet"),
         ("auto", 6, True),
         ("park", "sheet"),
@@ -481,7 +491,7 @@ def test_전처리_체인_다른_지형_먼저_떠_두고_설계_지형(monkeypa
         ("auto", 5, True),
         "precompute",
     ]
-    assert expected.read_text(encoding="utf-8") == "5"  # 예상노선 = 설계 지형 벌이 씀
+    assert expected.read_text(encoding="utf-8") == "design"  # 두 벌 같은 평면 노선
     assert not (tmp_path / SETS_DIR / "las").exists()
     assert not (tmp_path / "initial_design.lock").exists()
 
@@ -499,6 +509,7 @@ def test_전처리_체인_다른_벌_실패해도_설계_지형(monkeypatch, tmp
     summary = asyncio.run(chain.run_preprocess_chain(PID, 5))  # type: ignore[arg-type]
     assert summary == {"route_id": 1}
     assert log == [
+        ("seed", "classification"),
         ("switch", "sheet"),
         ("auto", 6, True),
         "clear",