Concerning the export did you had a look at this:
https://www.zeroshell.org/forum/viewtopic.php?t=3295&highlight=
I am not sure if it still works with the current release.
I have a problem with the current release. In the accounting panel I have entries for the user and for the used MAC address (as User-Id). Therefore I can not decide which is the right entry to use. In my case it seems to be a combination of both.
Do you also have 2 entries for one logged in user?
Regards,
Michael