diff --git a/src/ess/reduce/time_of_flight/fakes.py b/src/ess/reduce/time_of_flight/fakes.py
index 631c8491..94546abd 100644
--- a/src/ess/reduce/time_of_flight/fakes.py
+++ b/src/ess/reduce/time_of_flight/fakes.py
@@ -56,7 +56,7 @@ def __init__(
                 else tof_pkg.Clockwise,
                 open=ch.slit_begin,
                 close=ch.slit_end,
-                phase=abs(ch.phase),
+                phase=ch.phase if ch.frequency.value > 0.0 else -ch.phase,
                 distance=sc.norm(ch.axle_position - source_position),
                 name=name,
             )
diff --git a/src/ess/reduce/time_of_flight/lut.py b/src/ess/reduce/time_of_flight/lut.py
index b44b0108..0897364f 100644
--- a/src/ess/reduce/time_of_flight/lut.py
+++ b/src/ess/reduce/time_of_flight/lut.py
@@ -420,7 +420,7 @@ def simulate_chopper_cascade_using_tof(
             else tof.Clockwise,
             open=ch.slit_begin,
             close=ch.slit_end,
-            phase=abs(ch.phase),
+            phase=ch.phase if ch.frequency.value > 0.0 else -ch.phase,
             distance=sc.norm(
                 ch.axle_position - source_position.to(unit=ch.axle_position.unit)
             ),