Yeah, that makes sense. So the distance stacks for each resource individually.
Also, you must've broken a record right now, answering my question just a couple of minutes after I asked it. Such responsiveness is rare in a forum for an app! This really makes playing much more enjoyable, knowing that the creator is always ready to help and keeps in touch with the community.
Also, as this is a GPS-based game, what are your thoughts about Google making its Google Maps data open?