Simple solution. If ENY is tabulated using non active tower campers not labeled AFK, then idle kick them from the server say after 5 minutes. perhaps even an idle timeout for the GV that sits (jeep or wirble parked under a dense tree) unmoving while the player goes to lunch or what ever, 5 minutes on non movement (gun barrel or wheels/trackes) the server kicks them off. Then ENY will be based on actual people playing the game;of course if it continues to exclude the names marked AFK.
The reason i say this is i have often seen 10+ people in the tower for a long time with3 or 4 people in the air constrained with high ENY planes fighting 3 or 4 people on the other team (with few to no players in tower) flying uber birds. When both of these team are attacking the high ENY team it is no contest.
When you look at the numbers of players in the tower and such, it is only a "snap shot" of that moment when you opened the screen. If you closed the screen and opened it again to "refresh" the numbers it could very well show you the same numbers but it could also be a very different set of players in the tower, afk, and flying.
First look....
tower= players 1,2,3,4,5,6,7,8,9,10
afk= players 11,12,13,14,15
in air=players 16,17,18,19,20,21,22,23,24,25
Second look....
tower = players 3,4,5,6,7,8,9,10,22,23
afk= players 1,2,13,14,15
in air= players 11,12,16,17,18,19,20,21,24,25
In both looks, you have 10 in the tower, 5 afk, and 10 in the air but in your second look...
players 22 +23 where shot down and are now in the tower.
players 1 + 2 have hit the afk timer and have been moved to that list and no longer count toward ENY
Players 11+12 have moved their tank controls or have changed direction in their bombers on that long climb out to the city strat moving them from the afk list back to the in air list.
6 players changed but from one screen to the next you didnt see a difference.