The concept for this type of event is a lot of fun. Everyone but A is getting chased, and everyone but D is chasing. The lower the level, the earlier you start.
My feedback is for these event hosts to analyze the results of their events and adjust start times so that there is a fair distribution of ride categories ‘winning’ (assuming no one is lying about their category ;-).
I don’t have any statistics to back this up, but my guess is that, for example, the lead group of A’s finish first close to 100% of the time. And while some D riders may not get caught by some C riders, I’m also guessing that the front C riders catch the front D riders, and so on between A and B, B and C.
If I think of AVG w/kg, D is up to 2.4. If the front group of D’s worked their butts off (20% higher), they would average 2.9. For the front A group to catch them, they should have to average just over 20% above max, say 22% higher than 5.0 (6.1). My guess is the D’s avg close to max in a good race, the A’s under max, and they smoke them after 30 minutes into a 60 minute race. Make sense?