Number of layout options different for different activity profiles...

When I open the activity profile 'Road', data screens, map, 'layout and data fields' under the layout options menu there are 6 layout options (0-A, 0-B, 1, 2, 3, 4).

When I open the activity profile 'Mountain', data screens, map, 'layout and data fields' under the layout options menu there are only 4 layout options (0-A, 0-B, 1, 2).

As luck wouldn't have it, I want option 4 in the mountain bike activity. Can anyone tell me how I can make this happen please?