diff --git a/dlibrary/dlibrary.py b/dlibrary/dlibrary.py
index 5f0b489..223ed45 100755
--- a/dlibrary/dlibrary.py
+++ b/dlibrary/dlibrary.py
@@ -894,7 +894,7 @@ def unique_hierarchical_prefix_numbering(entries, start_point=0):
                     if not next_match:
                         return None
                     next_layer_start = pos + next_match.end()
-                    sub_numbering = unique_hierarchical_prefix_numbering(ents_idx, start_point=next_layer_start) or alphabetic_numbering(ents_idx, next_layer_start)
+                    sub_numbering = unique_hierarchical_prefix_numbering(ents_idx, start_point=next_layer_start)
                     if not sub_numbering:
                         return None
                     for sub_idx in sub_numbering:
@@ -902,7 +902,7 @@ def unique_hierarchical_prefix_numbering(entries, start_point=0):
 
             return numbering
 
-    return None
+    return alphabetic_numbering(entries, start_point)
 
 def alphabetic_numbering(entries, start_point):
     debug(f'Finding alphabetic numbering from start point {start_point} for {entries}')