Can you zero out an axis display when you are in the relative position screen? To me, this would be the primary use of relative position: suppose you touch off your reference tool on a gauge block, and you need to know the Z distance from the gauge to the top of your part, so that you can set a Z work offset in your desired work offset system (G54, etc). Zero the Z display in the relative position while the tool is still on the gauge. Now, the Z distance that you discover as you touch off the workpiece will be a useful figure. That's what I do on a Haas. Fanuc might be different.
First you get good, then you get fast. Then grouchiness sets in.
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)