diff --git a/src/cal_tools/agipdlib.py b/src/cal_tools/agipdlib.py
index 4a078dc45e5cf99a69b1c0df87faccb8961dd08e..454dea760eb5b508c9dac05146968ff75f14169e 100644
--- a/src/cal_tools/agipdlib.py
+++ b/src/cal_tools/agipdlib.py
@@ -1228,8 +1228,8 @@ class AgipdCorrections:
                 rel_gain[..., 1] = rel_gain[..., 0] * frac_high_med_pix
                 rel_gain[..., 2] = rel_gain[..., 1] * 4.48
             else:
-                # Intialize with fake calculated parameters of Ones
-                md_additional_offset = rel_gain
+                # Intialize with fake calculated parameters of Ones and Zeros
+                md_additional_offset = np.zeros((128, 512, self.max_cells), np.float32)
                 frac_high_med = np.ones((self.max_cells,), np.float32)
 
             self.md_additional_offset[module_idx][...] = md_additional_offset.transpose()[...]  # noqa