I've often wished for the same ability to jog the ends of the level dimensions. Story Levels can be offset, but its all or nothing, not individual like the grids.
You can manually offset the level dimension markers and move the text of same. Depending on how cluttered it gets, a little arrow, I draw mine with the spline tool, can help maintain clarity.
Make a wish if there isn't one for this. You have my vote.
Erika
Architect, Consultant
MacBook Pro Retina, 15-inch Yosemite 2.8 GHz Intel Core i7 16 GB 1600 MHz DDR3
Mac OSX 10.11.1
AC5-18
Onuma System
"Implementing Successful Building Information Modeling"