Yes to all the above and its still bugged even if i explore right up to the cap right it will still allow me to explore more at the reduced costs - I just did this actually; I explored up to the cap and then explored for another 233 acres beyond the median at the reduced rate of 13 Soldiers per acre and 2700 Gc per acre; afterwards my exploration costs soared to 35 soldiers per acre and 7400gc per acre
this is bugged and should be fixed