diff --git a/dlibrary/dlibrary.py b/dlibrary/dlibrary.py
index 785e626..92021ad 100755
--- a/dlibrary/dlibrary.py
+++ b/dlibrary/dlibrary.py
@@ -235,15 +235,17 @@ def complete_prefix_number_ordering(entries):
     unified_indices = list(unified_indices)
     unified_indices.sort()
 
+    min_delta_by_level = {}
     if len(unified_indices) > 1:
         for i in range(1, len(unified_indices)):
             cur = unified_indices[i]
             prev = unified_indices[i-1]
             for level in range(min(len(cur), len(prev))):
                 if cur[level] != prev[level]:
-                    if cur[level] - prev[level] > 2:
-                        return None
-                    break
+                    delta = cur[level] - prev[level]
+                    min_delta_by_level[level] = min(min_delta_by_level.get(level, delta), delta)
+    if any(delta > 2 for delta in min_delta_by_level.values()):
+        return None
 
     unified_indices.append(None)