Started over in this other thread.
(Thanks for the good idea, Rampa.)

This might need to be set on a "per row" basis.

For example, I like to use the STEP function a lot on my cameras.  I find it easy to make "cuts" that way; easier than using the camera switcher.  But I am constantly needing to change my keyframes from Linear to Step.  It would be nice if I could set my camera move keyframes to use the Step function by default.