diff --git a/resources/tester/helper_b05_station_roundtrip.cjs b/resources/tester/helper_b05_station_roundtrip.cjs
index 381362f8..c31ff5cd 100644
--- a/resources/tester/helper_b05_station_roundtrip.cjs
+++ b/resources/tester/helper_b05_station_roundtrip.cjs
@@ -72,6 +72,10 @@ out.shown = [fields.station.value, fields.remainder.value];
 out.untouched = fields.read(INTERVAL, true);
 fields.write(123.3721, INTERVAL);
 out.untouchedRaw = fields.read(INTERVAL, true);
+// 사용자가 놓은 119.8 — 다시 열면 5 + 19.8 로 보이고 그대로 읽힘
+fields.write(119.8, INTERVAL);
+out.r119 = [fields.station.value, fields.remainder.value, fields.read(INTERVAL, true)];
+fields.write(123.3721, INTERVAL);
 // 사용자가 잔여를 고치면 친 값으로
 fields.remainder.value = "5.2";
 fields.remainder.fire("change");
diff --git a/resources/tester/test_b05_station_roundtrip.py b/resources/tester/test_b05_station_roundtrip.py
index 0bdbd305..e0f84139 100644
--- a/resources/tester/test_b05_station_roundtrip.py
+++ b/resources/tester/test_b05_station_roundtrip.py
@@ -34,6 +34,7 @@ def test_칸을_안_고치면_실어_둔_측점_그대로(results):
     assert results["untouched"] == 123.37
     assert results["untouchedRaw"] == 123.3721
     assert results["retypedSame"] == 123.37
+    assert results["r119"] == ["5", "19.8", 119.8]
 
 
 def test_칸을_고치면_친_값(results):
@@ -49,3 +50,54 @@ def test_계획고_편집은_가까운_새_측점으로_옮김(results):
     }
     # 옮길 곳이 없으면 종전대로 지움
     assert "200.000" not in results["deleted"]["station_offsets"]
+
+
+# ── 서버 — 사용자가 놓은 구조물 측점은 소수 그대로(격자 붙이기는 횡단 측점에만) ─────────
+# 브레인 판정(다): 횡단 측점 · 파일 이름의 정수 m 격자 붙이기는 그대로 두고, 구조물 정본 측점만
+# 사용자가 놓은 소수 그대로 저장 · 다시 읽기. 임시 storage 에서만 씀(공유 storage 안 건드림).
+
+
+def _flat_sampler():
+    import numpy as np
+
+    class _Flat:
+        def sample_xy(self, xy):
+            count = len(np.asarray(xy, dtype=np.float64))
+            return np.full(count, 100.0), np.ones(count, dtype=bool)
+
+    return _Flat()
+
+
+def test_사용자_구조물_119_8_저장_다시_읽기_그대로(tmp_path):
+    from B05_Profile.B05_Profile_Engine_Sections import cross_filename, resolve_extra_stations
+    from B05_Profile.B05_Profile_Engine_Sections_Core import (
+        SectionGenerationOptions,
+        generate_sections,
+    )
+    from B05_Profile.B05_Profile_Structures_Repository import load_structures, save_structures
+    from B05_Profile.B05_Profile_Structures_Schema import StructureInstance
+
+    item = StructureInstance(
+        type_id="cross_drain_exposed",
+        placement="point",
+        chainage_m=119.8,
+        memo="메모만",
+        placement_source="manual",
+    )
+    save_structures(str(tmp_path), [item], base_revision=0)
+    _, loaded = load_structures(str(tmp_path))
+    assert [s.chainage_m for s in loaded] == [119.8]
+
+    extras = resolve_extra_stations(tmp_path, [])
+    assert [chainage for chainage, _ in extras] == [119.8]
+    sections = generate_sections(
+        [[0.0, 0.0, 100.0], [300.0, 0.0, 100.0]],
+        _flat_sampler(),
+        SectionGenerationOptions(extra_stations=extras),
+    )
+    chainages = [round(s["chainage_m"], 3) for s in sections["longitudinal"]["stations"]]
+    # 횡단 측점은 격자 120 으로 붙음(파일 이름 cross_00120m 한 장) — 정본 측점은 119.8 그대로
+    assert 120.0 in chainages and 119.8 not in chainages
+    assert cross_filename(119.8) == cross_filename(120.0)
+    _, again = load_structures(str(tmp_path))
+    assert [s.chainage_m for s in again] == [119.8] and again[0].memo == "메모만"