If your HEL-JFK-LAX-LAS flights are on 29/10 then the issue is that even if you take the 5pm flight to LAX there are no more flights to LAS after you land at LAX. What I would do is ask to get rebooked on the direct JFK-LAS flight (AA 2836). That way you'll avoid an overnight at LAX and will only lose 40 TPs.