diff --git a/tools/battery/score.py b/tools/battery/score.py
index d033a7239..6d213c039 100644
--- a/tools/battery/score.py
+++ b/tools/battery/score.py
@@ -298,17 +298,26 @@ def judge(entry, rep, run_note):
             # the reference is among the groups it offered, and the ONLY axis the two differ on is
             # one it named. A screw called wrongly where the row WAS measured meets none of them
             # and stays a failure.
+            # WHICH axis carries the disagreement is a property of the setting, and the two sides
+            # are named in different ones: the reference in the deposition's axis labels, ours - and
+            # SPACE_GROUP_SCREW_UNDETERMINED with it - in our own. Where the cells are a permutation
+            # of each other the two never meet: a deposited P 21 21 2 differs from our P 21 21 21 on
+            # c, while the same group written in our axes differs on b, the axis actually left open.
+            # So the axes are compared against the offered group, which is already in our setting;
+            # the reference being among the offered is a condition anyway, and a group offered under
+            # more than one setting passes if any of them fits.
             undetermined = set((rep.get("SPACE_GROUP_SCREW_UNDETERMINED") or "NONE").split())
             offered = [gemmi.find_spacegroup_by_name(x.strip())
                        for x in (rep.get("SPACE_GROUP_ALTERNATIVES") or "").split("|")]
-            differ = screw_axes_differing(space_group(rep.get("SPACE_GROUP_NAME"), r["sgno"]),
-                                          space_group(cand.get("sg"), cand["sgno"]))
-            if (undetermined != {"NONE"} and differ and differ <= undetermined
-                    and any(o and o.number == cand["sgno"] for o in offered)):
-                return n, ("unscored", "screw_undetermined",
-                           f"{r['sg']} vs reference {sg_cand}: the screw along "
-                           f"{', '.join(sorted(differ))} is undeterminable from these data "
-                           f"(offered {rep.get('SPACE_GROUP_ALTERNATIVES')})")
+            ours = space_group(rep.get("SPACE_GROUP_NAME"), r["sgno"])
+            for o in (x for x in offered if x and x.number == cand["sgno"]):
+                differ = screw_axes_differing(ours, o)
+                if undetermined != {"NONE"} and differ and differ <= undetermined:
+                    here = f" (here {o.hm})" if o.hm != sg_cand else ""
+                    return n, ("unscored", "screw_undetermined",
+                               f"{r['sg']} vs reference {sg_cand}{here}: the screw along "
+                               f"{', '.join(sorted(differ))} is undeterminable from these data "
+                               f"(offered {rep.get('SPACE_GROUP_ALTERNATIVES')})")
             return n, ("fail", "sym_screw", f"{r['sg']} vs reference {sg_cand}")
         cause = ("sym_under" if order < order_ref else
                  "sym_over" if order > order_ref else "sym_other")
diff --git a/tools/battery/test_score.py b/tools/battery/test_score.py
index 79d5d2e76..51898bc8a 100644
--- a/tools/battery/test_score.py
+++ b/tools/battery/test_score.py
@@ -93,5 +93,53 @@ class AcceptedAlternatives(unittest.TestCase):
                     score.alternatives(e)
 
 
+# A screw along an axis the sweep never recorded: an unanswerable question, not a wrong answer.
+# The cells are synthetic, and the second is the first cyclically permuted.
+ORTHO = [97.0, 108.0, 113.0, 90.0, 90.0, 90.0]
+ORTHO_PERMUTED = [113.0, 97.0, 108.0, 90.0, 90.0, 90.0]
+
+
+class ScrewUndetermined(unittest.TestCase):
+    def judge(self, ref_cell, undetermined, alternatives):
+        """Our P 21 21 21 on ORTHO against a deposited P 21 21 2 on ref_cell."""
+        e = {"id": "test_screw", "arm": "open",
+             "ref": {"sg": "P 21 21 2", "sgno": 18, "cell": ref_cell}}
+        return score.judge(e, report("P 21 21 21", 19, ORTHO,
+                                     SPACE_GROUP_SCREW_UNDETERMINED=undetermined,
+                                     SPACE_GROUP_ALTERNATIVES=alternatives), "")
+
+    def test_same_setting(self):
+        """The plain case: the reference is offered verbatim and the open axis is the one they
+        differ on."""
+        r = self.judge(ORTHO, "c", "P 21 21 2")
+        self.assertEqual((r["verdict"], r["cause"]), ("unscored", "screw_undetermined"))
+
+    def test_permuted_setting(self):
+        """The deposition's axes are a cyclic permutation of ours, so it names the open screw c
+        while we name it b. The comparison must be made in OUR setting - against the offered
+        group of the reference's number - or the rule misses a row it covers."""
+        r = self.judge(ORTHO_PERMUTED, "b", "P 21 2 21")
+        self.assertEqual((r["verdict"], r["cause"]), ("unscored", "screw_undetermined"))
+        self.assertIn("the screw along b", r["reason"])
+
+    def test_a_wrong_screw_still_fails(self):
+        """The open axis is not the axis the two differ on: in our own setting the disagreement
+        sits on b while the run says it could not determine a, so the b row WAS measured. That is
+        a wrong answer and stays one - the new framing must not turn every permutation into an
+        excuse."""
+        r = self.judge(ORTHO_PERMUTED, "a", "P 21 2 21")
+        self.assertEqual((r["verdict"], r["cause"]), ("fail", "sym_screw"))
+
+    def test_nothing_undetermined_still_fails(self):
+        """Every axial row measured: no rule to apply."""
+        r = self.judge(ORTHO, "NONE", "")
+        self.assertEqual((r["verdict"], r["cause"]), ("fail", "sym_screw"))
+
+    def test_the_reference_must_be_among_the_offered(self):
+        """An open axis alone does not excuse a group the run never offered."""
+        r = self.judge(ORTHO, "b", "P 21 21 21")
+        self.assertEqual((r["verdict"], r["cause"]), ("fail", "sym_screw"))
+
+
 if __name__ == "__main__":
     unittest.main()