Hey there,
the previous calculation model was inaccurate and not in sync with the CBL license terms. You can find the updated SQL queries used in OmniBack\bin\dbscripts\DP906.
You may check your IDB for unique long term protected objects that are no longer actively backed up. A quick exmaple. If you changed the hostname of a file server years ago and the object is still protected on a tape vaulted elsewhere while the same data is backed up now on a hostname this is also included in the calculation (handled as two objects). Having long term retention and frequent migrations could explain this.
Regards,
Sebastian Koehler