Someone took a beating here for checking oil qty on EICAS & tricking it on upper display.
I think there is no harm in small variations when one wants to monitor more carefully. Even browsing through pages in cruise is no harm done. As long as you are not screwed up about BOEING philosophy in your head every pilot should be given a little freehand to exercise his understanding in the cockpit when all is normal. (I m referring to only display pages and not touching switches)
Its a long haul a/c a pilot needs something to keep himself busy what's the harm in customizing the display a little bit?
regular browsing keeps the mind busy thinking, learning.