Active AP Reviewer users is reflected by the sum of:
1. users who have access to AP Check Review on the User Access page.
2. your unique AP invoice reviewers for a given month, OR if you are using the "Restrict AP Approvers in the Portal to Only Members of This Reviewer Group" portal settings, the users who are in this reviewer group with invoices in the current month.
3. your users that are listed in the Usernames tab of any HQ Reviewers that are set to reviewer invoices in Vista and are listed in the setting in number 2.
Go to Admin > Portal Settings > Review AP Invoices
If your AP Reviewer counts are higher than you expect them to be, make sure that you have the portal setting shown above filled in with the Reviewer Group that only contains the users you want to give access to the AP Portal. This will restrict the users who have access to AP to members of this group.
In this screenshot shown above, if the AP Reviewer for "AF" is listed as an invoice reviewer, it will count as two AP users because both AFisher and George will be able to review invoices.