Very well but I do have problem with his numbers, lets take a look.
First of all, in fairness, he has a total loss for Hurricanes and Spitfires at 932, which is very close to 915 losses for all of RAF fighter Command during the BoB as stated in "The Narrow Margin"(Wood and Dempster) How does he then get to the figure of 1120 kills for the combined total for the 109 and 110? Is he including losses of Bomber Command over Germany?
Total victories for the Hurricane and Spitfires are given as 1300 by Bergstrom.
German losses from combat, taken from the German Quartermaster general returns give a total of 1733 losses due to combat. This would be the minimum figure for German losses at the time. These losses are from the 10th of July to Oct 31, 1940.
This leaves us with at least 433 German combat losses not shot down by Hurricanes or Spitfires, a rather generous sum to be attributed to AAA and Defiants.
Bergstrom doesn't seem to have the same generous allowance for return fire from Luftwaffe bombers.
Other questions are also apparent when you don't have his full paper for review. For example what dates is he using for start and stop of the battle, how does he reconcile double claims between competing aircraft types ect.
Frankly I see too many glaring problems with this study.