Engine oil change interval

You have the recommended interval from your mechanic and the recommended interval from the oil manufacturer. But you are missing the number that you should start with - the one from vehicle manufacturer. If your vehicle came with a user manual, it's generally in the preventive maintenance section in that manual; if you don't have the manual, look online for your make & model.

Oil change intervals frequently specify both distance and time (e.g., "every 3000 miles or 3 months, whichever comes first"). 2000 kilometers is on the low side, but if you don't drive long distances, it may be an appropriate interval.