The newer arrival sensors use the arrival-sensor-ha.groovy device type. With this device, the presence timeout is set in the device preferences in the mobile app. The default is 2 minutes but you can set the timeout to 2, 3, or 5 minutes.
For the older arrival sensors, which use the arrival-sensor.groovy device type, the presence timeout defaults to 2 minutes as well but the timeout can be changed in the Hub utilities in the IDE. You can set the timeout between 2 and 10 minutes.