Uptime Limit variable for hotspot html pages

Is anybody able to tell me what (if any) is the variable to use for the total uptime limit of a hotspot user to insert in a webpage ?
I can find session-time-left which is the actual time the user has left, but not the total time or time limit allocated to the user.
The uptime variable is also available, but it only gives the uptime of the current session.
The same variable is available for bytes in and bytes out, but not uptime.

There doesn’t seem to be anything in the manual that I can find.

Thanks
Paul