Explanation
Arrival Window Start and Arrival Window End are fields on the Service Appointment that indicate when a technician is expected to arrive at a customer site based on travel time and service duration calculations. These fields can be shared with customers to set expectations around upcoming appointments. Scheduled End and Scheduled Start are fields on the Service Appointment that indicate when a technician is scheduled to start and end their service based on their availability and assigned time slots. These fields are not accurate indicators of when a technician will arrive at a customer site, as they do not account for travel time and service duration variations. References: https://help.salesforce.com/s/articleView?id=sf.fs_service_appointments.htm&type=5