The different field sizes have progressively more guns. So the small airfield as the town guns named one way, the medium town another, and the large field yet another. So the numbers for guns 1-8 are given to be different according to that table.
The OP must be talking about the maps not produced by AH. The offical maps loaded with the game are very limited information wise. the medium airfield map is missing altogether.
The "official" maps that come with the game are not produced by HTC...
Everything that is in the game, all game content is approved by HTC, it's there product, their game, their MAPS. We the customer pay HTC to use their product.