This move was almost certainly planned long before the merger. They announced construction of a massive, headquarters-sized campus in Westlake several years ago

This move was almost certainly planned long before the merger. They announced construction of a massive, headquarters-sized campus in Westlake several years ago, and they're already almost done building 3 of the huge office buildings (with 2-3 more to come). My guess is that the move is an entirely separate decision but was combined with this announcement for convenience sake.