I'm sure that the video was being held for a late October surprise, perhaps even the first couple days of November. The coordination behind the media was well in place. First, though, let's review two pertinent points.
1. The video was heavily edited, so context was not fully provided.
2. The video's content was such that, with proper media exploitation, the initial impact would highly negate Romney, but the same content would boomerang and help Romney, if he had enough time (in this case a week.)
This leads to believe that Obama needed battlefield surgery, and took what he could.