I did my best trying to find out what each field changes. Here are my findings:

Navigation Parent Item Styles: Changes both parent and child items
Navigation Link Hover Color: I couldn’t see any changes
Navigation Parent Background Color: Changes both parent and child background
Navigation Parent Hover Background Color: I couldn’t see any changes
Navigation Parent Current Menu Top Border: Works
Navigation Parent Current Menu Bottom Border: Works
Navigation Child Item Styles: Changes font, but not color and font size
Navigation Child Item Link Hover Color: Works
Navigation Child Item Background Color: Background stays white
Navigation Child Item Hover Background Color: Works
Navigation Child Current Menu Item Top Border: I couldn’t see any changes with this
Navigation Child Current Menu Item Bottom Border: Works
Navigation Child Item Box Shadow Color: Works
Navigation Child Item Top Border: Works
Navigation Child Item Bottom Border: Works