diff --git a/tests/saitests/py3/sai_qos_tests.py b/tests/saitests/py3/sai_qos_tests.py
index bd963fc118e..dec2dcabafa 100644
--- a/tests/saitests/py3/sai_qos_tests.py
+++ b/tests/saitests/py3/sai_qos_tests.py
@@ -4280,6 +4280,7 @@ def runTest(self):
                 # No additional packet margin needed while sending,
                 # but small margin still needed during boundary checks below
                 pkts_num=1
+                expected_wm = pkts_num_fill_min * cell_occupancy
             else:
                 pkts_num=(1 + upper_bound_margin) // cell_occupancy
             while (expected_wm < total_shared):