Ralph, the up/down arrows do not always move one to the next next.
Sometimes they hang up on the sliders, as mentioned.
The arrow keys toggle among 3 of the 9 buttons on the main settings panel.
The arrow keys adjust the BLUE color on one of the Background Colors.
And surprisingly, are NOT capable of adjusting the volume slider on the Music Settings panel.
I agree with Nicki that it's "weird". It also seems (to me) to be inconsistent from panel to panel. Only Jim can tell us if it's working as intended, or what.