diff --git a/lisainstrument/instrument.py b/lisainstrument/instrument.py
index bce2bbc72997f42eaf1a5a9fefc47920cc6e7848..8147e495a7555d221d0e7543f665f44a3079a903 100644
--- a/lisainstrument/instrument.py
+++ b/lisainstrument/instrument.py
@@ -684,7 +684,7 @@ class Instrument:
                 cumulative_trapezoid(np.broadcast_to(
                     self.clock_noise_offsets[sc] + self.clock_noise_fluctuations[sc],
                     self.physics_size),
-                dx=self.physics_dt, initial=self.clock_offsets[sc])
+                dx=self.physics_dt, initial=0) + self.clock_offsets[sc]
             )
 
         ## Timer deviations from TCB