You can change the labeling for an enhanced custom grid.
Manually changing the labeling for a grid can be useful for example when you are adding secondary grid lines before the first main grid line, and would like to change the formatting for the preceding secondary lines, but not for the secondary lines within the grid:
Using the same numbering format before and within grid
Using a different numbering format (preceding zero) before the grid
You can change one label individually or you can define arrange of labels for changing.