My experience is similar to Away2Maine, only better. I always use the app to book service. Within 24 to 48 hours, I get a text from the tech person telling me what he thinks, asking for more info, and he looks at the car logs. Then, I get a parts order notification, when appropriate, and the car is either scheduled for mobile service, if it can do the job, or an appointment at the service center, or the tech solves the problem remotely. Then I get notified the part has reached Tesla. The service is then performed where scheduled. I think most of the time it is less efficient to deal with the service center, because then you have no action taken by Tesla until just before you take in your car, even on something that can be fixed remotely or with mobile service. Why bother?