90847 Family Psychotherapy with patient Present
90846 without patient present
90849 Multiple-family group psychotherapy)
It's one of those and none of them are time dependent so You would charge however many units, for example if your fee is for 1 unit (1 hour) and you see them for 6 hours you would use that fee with 6 units. But I can guarantee you that you will only get reimbursement for ONE unit from insurance, they won't pay for multiple sessions on same day. Also you'll still want to get an authorization on file if needed but again, they will more than likely only approve one session. As a side note If that were my client, I would have to have them sign something if they want to pay out of pocket and I would need it to cover him for all of that time since it's time he could be seeing with other patients, a half a day seems a bit too much even if it is once a month.