I used to have my Rocky set to similar numbers.
When you take it apart for a deep clean youll see that the marked zero point is maintained by a bent screw. I suspect that it is none too accurate.
Have you done the plumbers teflon tape modification yet? This will stop the upper burr carrier from rocking and tilting due to the slop in the threads. It probably wont help with the setting number, but it will help with grind consistency.
A search of this site will provide complete details of this modification.
Enjoy Rocky, it works well.