diff --git a/src/base/abc/abcUtil.c b/src/base/abc/abcUtil.c
index 1b5d03b13..108514b51 100644
--- a/src/base/abc/abcUtil.c
+++ b/src/base/abc/abcUtil.c
@@ -1418,6 +1418,11 @@ int Abc_NodeCompareLevelsIncrease( Abc_Obj_t ** pp1, Abc_Obj_t ** pp2 )
 int Abc_NodeCompareLevelsDecrease( Abc_Obj_t ** pp1, Abc_Obj_t ** pp2 )
 {
     int Diff = Abc_ObjRegular(*pp1)->Level - Abc_ObjRegular(*pp2)->Level;
+    if ( Diff > 0 )
+        return -1;
+    if ( Diff < 0 ) 
+        return 1;
+    Diff = Abc_ObjRegular(*pp1)->Id - Abc_ObjRegular(*pp2)->Id;
     if ( Diff > 0 )
         return -1;
     if ( Diff < 0 )