LoT Season Order Expanded

The CW has ordered an additional four episodes for the current season of Legends of Tomorrow. This brings it to 17 episodes, one more than last season. I'm not sure how this is going to jive with the rest of the network's schedule. I was under the impression that most programs were going to get reduced seasons because they ordered too many shows. It's possible that either they had some wiggle room or something's about to be cancelled.