Limit working hours by services, not by providers


I'm working on a website where users can make an appointent for english courses. Each course will have only a professor and each professor can make more than one courses (in different days or hours, you know). Appointments+ looks pretty good to manage this untill you see that in my case, I need to limit the working hours by services (courses) and not by providers (professors). It would be easy to use the plugin just using "services" for "professors" and "providers" for "courses", but in the appointment registration form you say which is the "Service name" and which is the "Service provider". Is there any easy way to change the logic of the plugin to simply call "services" to the "providers" and vice versa?

Thank you in advance.