Section 18B. Three or more persons may associate themselves by written agreement of association, in a form furnished or approved by the commissioner of revenue, with intent to form a corporation for the purpose of acquiring a project which has been authorized and approved and which has been developed or is being developed in accordance with the provisions of this chapter or chapter one hundred and twenty-one B, or for the purpose of acquiring any severable portion of such project, including air rights or other interests in land therein. The persons who have executed such an agreement of association shall, before presenting the agreement of association to the state secretary for filing, submit to the housing board an application for its consent to the formation of such corporation. Such application shall specify the project or portion thereof which it is proposed to acquire, the terms upon which the same is to be acquired, and the amount of capital which it is intended to raise. If it is proposed that any changes in the plan for the original project as authorized and approved, or for the particular portion thereof, be made by reason of such acquisition, the application shall include such information concerning the proposed changes as the housing board shall require. If the housing board determines that the persons who have executed the agreement of association appear to have the ability requisite to perform the obligations and carry out the duties imposed by this chapter with respect to the project, and if it determines that none of the proposed changes, if any, alter the original project area boundaries, or significantly affect the objectives, standards, requirements and restrictions as to use, construction and design as set forth in said plan, or, where apt, as to the particular portion thereof, or the obligations and duties to be performed and carried out with respect to the project, or portion thereof, under this chapter it shall issue a certificate that it consents to the formation of the corporation. The agreement of association shall not be presented to the state secretary for filing, nor shall he file it, unless it is accompanied by such certificate. If any changes in the project are proposed in the application and if the housing board determines that any such changes alter the boundaries, or significantly affect the plan for the original project, or portion thereof, as authorized and approved, or the obligations and duties to be performed and carried out, as hereinbefore provided, the application shall be transmitted by the housing board to the mayor of the city or selectmen of the town in which the project is located and the procedure for approval of the application shall be similar to that set forth in section six, but with such modifications in procedure as the housing board shall determine to be appropriate for the accomplishment of the purposes of this section. A corporation organized under this section shall have all of the powers, rights, privileges, benefits and exemptions and shall be subject to all the duties of a corporation organized under section three; provided, however, that the periods of fifteen years or such further time as may be provided under section ten as set forth in sections ten and sixteen shall be computed from the date of organization of the corporation which initiated the project regardless of any default upon the part of such corporation which initiated such project.