It's a trick question (ok, it's a badly phrased question).
There's nothing stopping you doing such a ride, but the question is better asked as; were you to do such a ride which year would the points be assigned to, this or next?
What about a 600 where you do equal riding on both Oct 31st and Nov 1st?
What about a 400 on October 31st that you finish at 8am on Nov 1st?
What about a 300 on October 31st that you finish at 12:01am on Nov 1st?