I have noticed an issue where my Zoho Mailbox is showing my Used Storage as much greater that the Sum of my individual Mail Folders (i.e. Inbox, Sent Items, etc.)  

For example, currently when I go to Control Panel -> Mail Storage -> Used Storage shows 4.08 GB Used of 5.0 GB

But when I go to Control Panel -> Settings -> Folders, the sum of all folders including archives totals only approximately 100 MB.

Can you please help me understand why my Used Storage is showing 4.08 GB?  

Thank you.