These often relate to basic machine settings, such as pulse per millimeter/inch, and maximum feed rates.

I can provide more targeted guidance or help decode specific parameter behaviors for your system. Share public link

Fanuc intentionally hides 9900-series parameters because:

Axis motion, feed rates, acceleration/deceleration, and servo tuning.

Altering option parameters will void your manufacturer warranty. How to View and Backup FANUC Parameters