That's kind of the jist I got as well. I was speaking with Patrick De Beer with Mugabe Safaris, and he said he operates on 13000 acres and his herd is "free ranging". He also said that his herd are born and bread on the property, and are not imported in for any specific hunt.
All total with air fair and transfers, a 7 day hunt would run around $18K US. This is somewhat cheaper than I've seen on hunts elsewhere. I would really love to go to Tanzania and kill 2 buffalo on one trip, but the total cost on those hunts are $30k plus.