If you want to combine two services and offer a different appointment duration for a combined booking, you can do this as follows:
Go to Company > Services and edit the desired service. Within the service, click on the "Advanced Settings" tab and activate the Different duration when combined with other service function.
In our example, Service B has a regular appointment duration of 120 minutes.
The value of 75 minutes is stored in the Different duration field when combined with another service for "Service B".
Here, we assume that "Service B" with 120 minutes and the service "Addition B" with 60 minutes are booked online.
In our example, the available appointments are then suggested with a total appointment duration of 135 minutes (Addition B 60 minutes + Service B 75 minutes).
Note: This setting cannot be used if the Multiple Booking or Multiple Capacity options are enabled. The other appointment duration is only taken into account when booking an appointment online, not when an appointment is entered manually in the calendar.