I have also seen that in the CAS MODE settings the format for STANDARD numbers must be set to the number of decimals but not in the START mode. Attached image.
You should ignore that entire line in CAS Settings, since the Prime ignores it too. Neither the "Number Format" CAS Setting, nor the "number of digits" CAS Setting, have any effect in any way on anything.
Disclaimer: The above is true at this time, and has been true for several years, but might change in future firmware updates.
Yes, I hope it does change in future software updates.