https://www.edmunds.com/car-maintenance/oil-life-monitoring-systems.html
"Electronic sensors throughout the drivetrain send information about engine revolutions, temperature and driving time to the car's computer. The data is run through a mathematical algorithm that predicts when the oil will begin to degrade."
Please refer this.
I have done 4400km now, and showing 7600km oil life. As I thought before, it might due to long journeys. (Less engine running time, etc)