diff --git a/experiments/check_preconditioner_benchmark.py b/experiments/check_preconditioner_benchmark.py
index 75d6c7c..08b5cc0 100644
--- a/experiments/check_preconditioner_benchmark.py
+++ b/experiments/check_preconditioner_benchmark.py
@@ -120,7 +120,9 @@ def inspect_case_artifacts(folder):
     check('action_checks_present', len(action_rows) == 2 and
           {row['role'] for row in action_rows} == {'baseline', 'candidate'})
     for row in action_rows:
-        expected = by_role[row['role']]['variant'] == 'independent'
+        measured = by_role[row['role']]
+        expected = measured['variant'] == 'independent' or (
+            measured['variant'] == 'gravity-schur' and int(measured['schur_correction_sweeps']) == 0)
         check(row['role'] + '_action_variant_matches', row['variant'] == by_role[row['role']]['variant'])
         check(row['role'] + '_equivalence_requirement_recorded',
               row['context_equivalence_required'] == ('1' if expected else '0'))
diff --git a/experiments/test_preconditioner_benchmark_checker.py b/experiments/test_preconditioner_benchmark_checker.py
index 25ad4e1..f3820a4 100644
--- a/experiments/test_preconditioner_benchmark_checker.py
+++ b/experiments/test_preconditioner_benchmark_checker.py
@@ -206,6 +206,25 @@ class BenchmarkCheckerTests(unittest.TestCase):
                         lambda data: data[0].update(context_equivalence_required=0))
         self.assert_no_claim(checker.inspect_case(self.folder))
 
+    def test_zero_sweep_gravity_control_requires_default_equivalence(self):
+        for variant, sweeps, equivalent in (('gravity-schur', 0, True),
+                                            ('gravity-schur', 1, False),
+                                            ('stellar-ldu-gravity-schur', 0, False)):
+            with self.subTest(variant=variant, sweeps=sweeps):
+                self.make_case()
+                def summary(data):
+                    data[0]['schur_correction_sweeps'] = 0
+                    data[1].update(variant=variant, schur_correction_sweeps=sweeps)
+                self.alter_rows('preconditioner_summary.csv', summary)
+                self.alter_rows('preconditioner_actions.csv', lambda data:
+                                data[1].update(variant=variant, context_equivalence_required=int(equivalent)))
+                result = checker.inspect_case(self.folder)
+                self.assertTrue(result['passed'], result)
+                if equivalent:
+                    self.alter_rows('preconditioner_actions.csv', lambda data:
+                                    data[1].update(context_equivalence_required=0))
+                    self.assert_no_claim(checker.inspect_case(self.folder))
+
     def test_omitted_input_or_output_hash_cannot_support_speedup(self):
         for key, remove in [('input_state_hashes', str(self.snapshot)),
                             ('output_hashes', 'candidate_normalized_linear_defect.txt')]: