Hi Joseph,
These are some of the notes for GSS (Guided self service).
1487247 - Guided Self Service: Data Volume Management - Prerequisites
1609155 - Guided Self Services
In our experiences with this tool (DVM Workcenter), we have also identified some inconsistencies in the reports that DVM is generating and what the ERP managed system has is for ex: DB02.
for your issue , although it's better to raise an incident with SAP .
Regards,
Satya