Each game probably has a different formula to work out a number of points for wins/losses or positions i.e 1st 2nd 3rd which is probably added/subtracted for the overall, so even if they couldn't add a scoreboard to the general leader board of an overall score, it would be nice to add on the overview, how your position on the leader board is determined i.e a certain formula, how many points each win/ loss gives so if people wanted to they could figure out their total score themselves and how many more wins they need to surpass the person above them. Would add greater understanding on the game like Tall said ^