Supervisor Can’t See Subordinates Departments in Reports

We have several supervisors over users in many departments. When the role permission is set to restrict access based on Department – own and subordinate only, the subordinates departments do not show in the reports, only the current users department shows. I am aware of this,

“Any account in the Chart of Accounts list that does not have an assigned department is not subject to the own, subordinate, and unassigned or own and subordinates only restrictions.”

Seems pointless to set up an account for every department.