Official: OVERALL

The OVERALL ranking will change depending on who is leading the event while you are watching.

During race progress

Ride time - this is the current course riding time of the competitor.
Timebar penalty - As a competitor reaches a checkpoint the penalties for NOT reaching that checkpoint are removed. If a competitor reaches all checkpoints the timebar time shown becomes [blank] OR time penalties remain for any checkpoints not reached.

Day4 - this is the track ride time including any Offroad day 4 time penalties for GPS offtrack, for not reaching CP's, for being timebarred at checkpoint(s) and any time manual penalties given. (during the race includes time penalties for checkpoints not yet reached)
Difference  +0s (=zero seconds) is the fastest competitor. Example=If the time shown for a competitor is +2m30s this means the competitors Differential time is +2 minutes 30 seconds more than the fastest competitor.
 

When race completed

Total time - This is the 'total time' (OVERALL) for the event including ride time, and any timebarred penalties, manual penalties, GPS off track penalties given. 
Total Difference time - This is the OVERALL difference  between the fastest Offroad day 4 competitor and all other competitors. The fastest OVERALL competitor having +0s (=Zero seconds)