These huge clinical hours show the importance of "mean vs median".
You see this alot for PA school. The average PA matriculant has 3500 hours of human patient contact. But the median PA matriculant only has 1400 hours of HCE. I suspect a similar type of thing is going on here.
Here is a potential example: You could have say 10 people in the class who worked 5 years or so in a clinical field such as a phlebotimist and accumulated 12,000 hours in that time(there are non trads like this in many schools). In a class of 100 if 90 people on average have 500 hours of clinical experience but you add those 10 people, suddenly you have a situation where the "a matriculant on average has 1600 hours of clinical experience", when in reality the median is probably close to 500.
While it's true Rush values clinical experience and community service, I dont necessairly buy that they will look at someone(particularly someone who is a relatively traditional applicant) as having say 800 hours of clinical experience and not being satisfied with that and looking down on that total as insufficient.