Invoice Approval with 'Not required' Status

When running invoice approval process (after setting up AME rules and so)  and requester has the approval authority to approve the invoice the invoice is automatically approved but status changes to 'not required', it should be approved, isn't it?.

1- Invoice Approval rule is setup within AME
2- Payable Options are setup to require Invoice Approval
3- Workflow Deferred Agent listener is scheduled
4- Standard invoice is entered and Approval is Initiated using Actions >
Initiate Approval
5- Approval Status changes from Required to 'Not required' .
6. If using the "Test Workbench" one rule apply and the status is APPROVED

If the Invoice is autoapproved, why the invoice status is not updated to APPROVED?