Sec. 4. A plan of reorganization under this chapter must be adopted by:
(1) a vote of not less than two-thirds (2/3) of the members of the board of directors of the mutual insurance company; or
(2) in the case of the formation of any intermediate stock insurance holding company that is not concurrent with the formation of the mutual insurance holding company, by a vote of not less than two-thirds (2/3) of the members of the board of directors of the mutual insurance holding company.