How to rename individual sprite slice without creating new fileID in meta file using code?

Hi guys, after sliced a sprite sheet, I noticed that if I rename each individual sprite slice manually in Unity, the 'fileIDToRecycleName' session of the meta file for that sprite will stay cool (only name changes, while the fileID remains the same). However, if I do it using code, the 'fileIDToRecycleName' session will expand, reassigning the new name to a new fileID. See below:

 fileIDToRecycleName:
             21300000: name_0
             21300002: name_1
             21300004: name_2
 //if manually rename in unity the above will change to:
 fileIDToRecycleName:
             21300000: newname_0
             21300002: newname_1
             21300004: newname_2
 //if rename in code then:
 fileIDToRecycleName:
             21300000: name_0
             21300002: name_1
             21300004: name_2
             21300006: newname_0
             21300008: newname_1
             21300010: newname_2

My code is like this, similar to line 215-267 of https://github.com/eppz/Unity.Library.eppz_kit/blob/master/Editor/EPPZEditor_SliceRenamer.cs

         ...
         // Locate asset, get meta.
         path = AssetDatabase.GetAssetPath(texture);
         textureImporter = AssetImporter.GetAtPath(path) as TextureImporter;
         SpriteMetaData[] sliceMetaData = textureImporter.spritesheet;
 
         // Naming loop.
          for (i...)
         {
             string eachName = ...;
             ...
             sliceMetaData[i].name = eachName; 
         }
 
         // Save settings.
         textureImporter.spritesheet = sliceMetaData;
         EditorUtility.SetDirty(textureImporter);
         textureImporter.SaveAndReimport();
 
         // Reimport/refresh asset.
         AssetDatabase.ImportAsset(path, ImportAssetOptions.ForceUpdate);