Dear David,
If I understand you correctly, you are in need of the option for the Login One! plug-in to prevent multiple log-ins for certain ('admin-defined' I suppose) Super User accounts. You are referring to 'super admin' accounts, but these do not exist in a standard J3 install.
On the plug-in product pages, as well as in the plug-in documentation, it is stated very clearly that Super Users are always allowed multiple log-ins. In other words: the plug-in does not (and cannot) restrict Super User accounts in their max number of concurrent log-ins. The reason for this is straight forward: a Super User should have access to both the website's front- and back-end at all times and without restriction, so that they cannot be locked out from the website.
Also, such option would be ineffective, because a Super User would have access to the Joomla! back-end and he/she could simply change the plug-in configuration to allow for multiple log-ins.
However, your goal can be achieved. I suggest that you create an additional and special 'Super Admin' user group to which you assign your paying clients, thus preventing multiple log-ins for these users.
If you need assistance in configuring this, please let us know by sending an email to This email address is being protected from spambots. You need JavaScript enabled to view it.
EDIT: The Super User group that is never blocked by the plug-in, is the Joomla! 3.x default Super User group with ID #8.
If you create an additional user group, this will always have an ID that differs from #8 and it will therefore not be treated by the plug-in as the default Super User group and can therefore be denied multiple concurrent log-ins.
