It seems as though teleport battlestations will not fire upon bombers of their own accord. I think this is because the bombers's shields are too powerful to be harmed by the teleport battlestation fire. It seems that the mark IV battlestations can damage them, but the I - III ones just sit there and do nothing. Would it be possible to allow the level I - III battlestations cause some damage to the bombers? Note that we generally face Mark III to Core bombers, so it could just be a result of the level of the bombers.
