How are they recorded?

The last big battle i was in ended with JackinIrons shooting me. 
http://www.perp-kill.net/?m=view&id=5252

How ever before this epic one shot while i was at 1/2, I had received damage from at least 4 different nova members. RGwillow for sure hit me hard with his wasp. However I either broke his lock or ran back off the front line just long enough to rep back up caused his damage to not show. Or he died to AOE, and because he died before me his damage is not on my killmail?

Any insight on this.?