No, the 1/3 is just an amount that seems to allow a little sleep. The doc told me I could quit with meds and take the risk. He said it was best for me not to quit cold turkey even with meds, due to possible risk of seizure (living alone) and due to high blood pressure. And a counselor told me it would not be a good idea to quit cold turkey in advance of detox, due to my rapid onset of withdrawals (6 hours) and the reasons above.
And yes, I'm fortunate to have choices.
Thanks for all your replies.