The car has a secondary parking lock, you can hear it engage when you hit the power button the second time to shut accessory off. You can also do simple check to verify that your lock is engaging;
1. Start car, select neutral.
2. Step out and apply pressure on door/frame to ensure it will roll. (make sure car it's set on level ground and give yourself room.)
3. Push start button (shut engine off)
4. Push again (should still roll)
5. Push start button again (turn off accessories / parking lock)
6. Attempt to push car again, dct should still be in neutral, but car should not roll at this time!