I was meant more that you could create a timer to check that netprop data every 5 seconds or so and collect the updated number vs having to capture and process every infected death event. In the end your getting what you need which is the total number of kills for the common infected and headshots against them.
I have this plugin running now on one host and will install it on 6 more here in the next 24 hours. All will share the same DB so the ranks will be spread across the hosts in more of a global style instead of per server.
http://stats.blacktusklabs.com/l4dstats/index.php
-Teddy