AC charges "per provider." NOt per office or per computer. So you would pay one fee for as many offices or computers as you wanted. But you would pay extra for another MD or an NP or PA.
It sounds like by registration you mean scheduling appointments and inputing the patient demographics. There would have to be an AC interface with your current scheduler to do that. For example, we use Appointment Quest for our scheduler. We download the schedule every morning. AC also imports the address and teleophone of the new patients (but not the insurance info). We type in the rest whne the new patient arrives after they fill out our hard copy registration forms.