A discrepancy in database size can occur when one or both databases contain gaps where data no longer exists. This can occur when files get deleted and the database does not get compressed.
To get your databases closer in size, we suggest performing the maintenance tasks located in the UI here:
Admin --> Advanced --> Maintenance: Compress the Internal Database and Prune Unreferenced Data
After running these tasks, you could consult with your DBA to perform a compression on both databases, particularly with the following tables: