If any disappearing social purpose corporation in a merger is a close social purpose corporation and the surviving social purpose corporation is not a close social purpose corporation, the merger shall be approved by an affirmative vote of at least two-thirds of the outstanding shares of each class, or a greater vote if required in the articles, regardless of whether that class is entitled to vote thereon by the provisions of the articles, of the disappearing social purpose corporation. The articles may provide for a lesser vote, but not less than a majority of the outstanding shares of each class.