Unless I am the victim of an Arma glitch that will make this post irrelevant the next time I login to the game, It seems a completely arbitrary and pointless decision to force you to only have ONE of these design types, instead of both. Especially infuriating if you didn't know such a limit existed in the first place !
Also the 140m limit ? Can't you just make it so that it is 'not within 20m of a road' and 'not inside an Arma building' ? The system as it is now is very glitchy. Sometimes it says ''you cannot build within 140m of a city', and if you logout and in again and try in the same spot again it accepts your build no problem.