hmm.. Just casual observations I find its usually 10x for me and I have all 10 lv 10 relief stations :P I am not trying to prove or disprove his idea/theory.. Just coming from my casual observations. My advice.. Get more food. Don't use Cav's in mass to transport food or anything else unless you need it quickly. If you can wait on trans then they will be the less food heavy one to use. and well the longer the distance the more food it will use. Just keep enough food to move things around. Personally I would prefer reinforcing or transporting to be free.. but If it was free then there would be one less variable we as players have to deal with in playing the game. Less variables = less interesting game = less players.

Oh one more piece of advice. 100% resources.. one or the other.. all wood all iron etc. You will want this setup by the time you hit your 4th city. If you want an all food city then 1 is enough. But even that isn't needed due to npc farming. Get your npc farming setup properly and you wont need a food city as you will have plenty of food coming in.