Hi Meg, sorry you're going through this but congratulations on deciding to quit. I don't know enough about subutex to give you a good answer but if you're patient someone on here will respond. Things are a bit slow here these days so you may have to wait a few days.
Are you working with a sub clinic? They should help you with this maintenance of subutex. 16 mg is the target dose. When you say it isn't working, what do you mean?