diff --git a/dpti/lib/utils.py b/dpti/lib/utils.py
index 354e426..0190c02 100644
--- a/dpti/lib/utils.py
+++ b/dpti/lib/utils.py
@@ -556,7 +556,7 @@ def get_task_file_abspath(task_name, file_name):
 
 
 def integrate_range_hti(all_lambda, de, de_err, scheme="s"):
-    new_lambda, i, i_e, s_e = integrate_range(all_lambda, de, de_err, scheme="s")
+    new_lambda, i, i_e, s_e = integrate_range(all_lambda, de, de_err, scheme=scheme)
     # print('debug:range_hti', new_lambda[-1], all_lambda[-1])
     if new_lambda[-1] != all_lambda[-1]:
         if new_lambda[-1] == all_lambda[-2]:
diff --git a/tests/test_lib_utils.py b/tests/test_lib_utils.py
index f801ff6..8e9b0b2 100644
--- a/tests/test_lib_utils.py
+++ b/tests/test_lib_utils.py
@@ -152,6 +152,17 @@ def test_lamb_array_even(self):
         self.assertAlmostEqual(stt_err1, stt_err2, places=8)
         self.assertAlmostEqual(sys_err2, sys_err2, places=8)
 
+    def test_trapezoidal_scheme_is_forwarded(self):
+        """HTI range integration must honor the caller's selected scheme."""
+        lambdas = np.array([0.0, 1.0, 2.0])
+        values = lambdas**2
+
+        result, _, _ = integrate_range_hti(
+            lambdas, values, np.zeros_like(values), scheme="trapezoidal"
+        )
+
+        self.assertAlmostEqual(result, 3.0)
+
 
 class TestRelativeLinkFile(unittest.TestCase):
     @classmethod