Can I change end time of service in Appointment+ ?

I've got several questions:

1. After a visitor has made an appointment on the website, the service provider (or webmaster) wants to add additional time to the appointment. Before confirming the appointment, I can change the start time of an appointment, but I definitely want to change the end time instead. Do you have a code available?

2. I've integrated Google Calender successfully. I've used two-way integration, however, I've switched back to A+ --> GC due to a problem. When adding an appointment in Google Calender it is added to the reserved by Google Calender section, however, always assigned to the service 'Grote beurt' (2 hour job). I want to make sure that the appointment is assigned to the right service. How can I change the service? The field is blocked right now. Or do I have to type some specific text in Google Calender?

I prefer to use Google Calender as leading agenda.

3. I would like to set-up the Google Calender on an Android phone. Since the agenda in not primary, it will not sync to my phone. Any experience with synchronising two or more agenda's?