Update access-tiers-best-practices.md

Author: fhryo-msft

articles/storage/blobs/access-tiers-best-practices.md

@@ -66,6 +66,8 @@ The following chart shows the relative impact of packing files for the archive t
 > [!div class="mx-imgBorder"]
 > ![Chart that shows the impact on costs when you pack small files before uploading to the archive access tier.](./media/access-tiers-best-practices/packing-impact-archive.png)
 
+To model and analyze the cost saving of packing files, see **Packing Saving** tab in this [workbook](https://azure.github.io/Storage/docs/backup-and-archive/azure-archive-storage-cost-estimation/azure-archive-storage-cost-estimation.xlsx).
+
 > [!TIP]
 > To facilitate search and read scenarios, consider creating an index that maps packed file paths with original file paths, and then storing these indexes as block blobs in the hot tier.