Claim back space from deleted Time Machine backups

From MyBookLive.Local Web UI / Backups, I deleted a Time Machine backup (about 200 GB).  I then noticed that the usage was still 500 GB / 3 TB while I was expecting 300 GB / 3 TB. 

I could not connect to the MyBookLive-backup share.  How can I claim back the 200 GB?

What if you reset the MBL in case it just needs to be refreshed?

Total usage is 799 GB now.  From shares, 382 GB is occupied.  I presume the difference (419 GB) is used by backups.  How can I find the details?