The storage space shown by Spanning Backup for G Suite will vary from that shown by Google.  Here are a few reasons why:

Versioning:
Spanning backs up all the versions of your files, and counts each version as a separate file which leads to additional storage utilization. Google only counts the latest version of your files and as a result, the storage space utilized is much lower.

Shared files:
If you have opted to backup shared Google Drive files, they will add to your storage space used. Google shows storage utilization only for the owner of the shared files so even if the Drive file is shared with you, it will not count towards your storage space utilization.

Native Google Docs:
Google does not count their native documents, such as Google Docs, Slides, or Sheets, towards their storage space. Spanning backs up these files, and counts them towards the storage space for the users.

We Never Delete:
Our storage space totals will always be more than Google’s since we never delete your data - that way you can always recover your files, even if you delete them from G Suite.

If you have any additional questions, please reach out to support@spanning.com.