Even with full practice management, the accounts payable is not really a "routine" function/service. I have never offered it because I do think it's just too much work and I also think there needs to be a more hands on approach from the office when handling all the bookeeping.. you are talking deposits, accounts payable, payroll, etc. It's just not a routine service, if you want to add it as an extension to your services I guess you could as long as you feel confident enough and also I would say, in my opinion, it would a service worthy of it's own pricing for a whole separate service.