diff --git a/backend/tests/test_drop_registers_matching_last_verified.py b/backend/tests/test_drop_registers_matching_last_verified.py
index 0957b88..7849e2e 100644
--- a/backend/tests/test_drop_registers_matching_last_verified.py
+++ b/backend/tests/test_drop_registers_matching_last_verified.py
@@ -5,9 +5,11 @@ from services.control.exporter_monolith import (
 
 
 def test_drop_registers_skips_reg178_when_mask_matches():
-    # last_verified contains extra bits beyond 0x0030; we still want to skip if bits 4–5 match.
-    registers = [(178, "grid_peak_shaving_switch", REG178_PASSIVE)]
+    # last_verified contains extra bits; reg178 is a bit field and exporter uses RMW.
+    # We want to skip if the relevant bits match (bits4–5 and, if present, bits0–1).
     last_verified = {178: 12030}  # real-world example from home-01 (bits4-5 still == 0b11)
+    expected_rmw = (int(last_verified[178]) & ~0x0030) | int(REG178_PASSIVE)
+    registers = [(178, "control_board_special_1", int(expected_rmw))]
     out, skipped = _drop_registers_matching_last_verified(registers, last_verified)
     assert out == []
     assert skipped == [178]