I saw this posted on board game geek
boardgamegeek.com/thread/403683
It seems that infest command center works even if there is no battle in the area. This makes it much easier to get infested terrans than I had previously thought. It also contradicts the wording of the technology, so is an intent vs. printed wording issue.
A lot of these questions are building up. An F.A.Q. update would be nice.