diff --git a/csaxs_bec/scans/lamni_fermat_scan.py b/csaxs_bec/scans/lamni_fermat_scan.py
index 7ef4394..c991314 100644
--- a/csaxs_bec/scans/lamni_fermat_scan.py
+++ b/csaxs_bec/scans/lamni_fermat_scan.py
@@ -461,8 +461,10 @@ class LamniFermatScan(ScanBase):
             -np.sin(alpha) * stage_x_with_stitch + np.cos(alpha) * stage_y_with_stitch
         )
 
-        # FIXME: We are checking stage_x_rot vs fovy. This needs to be clarified if this is correct
-        # once LamNI is back in operation. We keep it like this for now.
+        # stage_x_rot is checked against fovy (and stage_y_rot against fovx) because alpha
+        # includes a fixed ~90 deg mechanical offset (-300+30.5 deg) between the piezo's
+        # physical axes and the angle=0 sample/beam frame that fovx/fovy are defined in.
+        # So stage_x_rot tracks the beam-frame y-extent, and stage_y_rot the x-extent.
         return (
             np.abs(stage_x_rot) <= (fovy / 2)
             and np.abs(stage_y_rot) <= (fovx / 2)