If you click "overall" and it shows a bunch of points, that's points from the various charts (0 points for first place, 1 for 2nd, 2 for third, etc) in a group, all added up, to give you an overall score. Done automatically.
THere's also some places where "overall" shows a bunch of times, which are just the normal "times" -- they don't count twice, there's just an extra link, that's all.
I always assumed it was legal to submit chaotix extra times/rings on chaotix normal times/rings charts, and have done so in the past both here and on cyberscore. Furthermore I recall having asked about this very issue and being told it was okay.