I was more thinking like something for the DA traffic accounting for a user.. Like if the user is allowed 5GB traffic / month, it will also count the traffic he is using on the shell
There's no way to track that; even if you could force your users to login through their own domain name and no other, the logs only track login time; they do not track logout time.
And there's no real way to track the data the user causes to be moved.