Agreed. I thought the same thing. Also, oldest servers are usually in
the beginning of the block, since we tend to start from the beginning and
work towards the end (well, perhaps I speak for myself). The servers
around longest are also probably more likely to have more information on
them and be more useful: Take webservers, for example. As time passes,
I've seen more and more activity to our oldest webservers simply because
there are more links on the web, more content (I think it was Einstein who
first figured out time and content are related) and more entries in search
engines.
And let's not forget our routers, which are usually .1 in the first /24 
Steve