The Permission ACL_M_REPORT is the permission to close and delete reports. It would be fine, if the permission ACL_M_REPORT could be splitted into 2 separate permissions close and delete reports to allow the moderators to solve a report and close it, but make sure the administrator have the possibility to check the report afterwards, if any user is complaining the action of the moderator.
For the permission ACL_M_PM_REPORT (reports of private messages) I suppose the same change.