This only affects the grid drawings and moreover only those who are drawn as planes, not as lines. The functions for grid lines have a "coveredGridUnits_rel" parameter in their signature, which is missing for grid planes, because in most cases more than 2 or 3 grid planes will make the grid display messy and unreadable. Though if you still want to draw more grid planes you can do so with this global setting. In many cases if you want to see a wider section of the grid it may be better to use gridlines instead of rasing this value for gridplanes.