Allowed Logon Version and SQLNET.ALLOWED_LOGON_VERSION

 I'm slogging through Policy Violations identified in our Oracle Enterprise Manager.  I'm currently working on the following Warning:

Listener, Allowed Logon Version:  Ensures that the server allows logon from clients with a matching version or higher only.  Recommenation:  Set the parameter SQLNET.ALLOWED_LOGON_VERSION in sqlnet.ora to the server's major version. Setting this value to older versions could expose vulnerabilities that may have existed in the authentication protocols.

I set the parameter in my server's sqlnet.ora file, but the warning won't go away.  Clicking on the details shows the "Allowed Client Logon Version" is now 10 (previously it was DEFAULT), but it shows "Database Version" is NA.