My impression was that Urahara's exile was, at most, months before the events in the arc. I mean, hiding<em>it</em>inside<em>that person</em>and then<em>doing that thing</em>only makes sense if it's all quick quick quick. And since<em>that thing</em>is one of the greater potential influences in the RI SPT Incident, I expect that Karakura Town has a new shinigami assigned to it already.