(1) The Redevelopment Commission shall upon the issuance of a certificate of convenience and necessity pursuant to Section 18 of this Act (unless the order by virtue of which the certificate was issued has been suspended pursuant to subsection (2) of Section 33 of this Act) proceed to a prospective determination of the Development Cost of the Development. In connection with such determination the Redevelopment Commission shall hold a hearing and may make such inquiry or investigation, and examine such witnesses, books, papers, accounts, documents and contracts and require the filing of such data, as it may deem of assistance. The Redevelopment Commission shall require the Neighborhood Redevelopment Corporation to disclose every interest of its directors in any transaction under investigation. The Redevelopment Commission shall have power to investigate all such transactions and inquire into the good faith thereof, to examine books, papers, accounts, documents and contracts of Neighborhood Redevelopment Corporations, construction companies or other companies or of firms and individuals with whom the Neighborhood Redevelopment Corporation shall have or shall have had financial transactions, for the purpose of enabling it to verify any statements furnished, and to examine into the cost of Real Property acquired or proposed to be acquired by such Neighborhood Redevelopment Corporation. Upon the conclusion of the hearing, the Redevelopment Commission shall determine of its own judgment the prospective Development Cost and shall issue to the Neighborhood Redevelopment Corporation a certificate stating the amount thereof as so determined. The amount as so determined shall thereafter be conclusive upon the Redevelopment Commission.
     (2) A Neighborhood Redevelopment Corporation may, at any time, whether prior or subsequent to the completion of its Development, whenever it appears that the actual Development Cost will be greater in amount than the prospective determination thereof made pursuant to subsection (1) of this Section, apply to the Redevelopment Commission for a determination of additional Development Cost. The Redevelopment Commission shall, upon such application, proceed to the determination thereof, in the same manner and with the same authority as provided by subsection (1) of this Section. Upon the conclusion of its hearing and the determination of the application, the Redevelopment Commission shall issue to the Neighborhood Redevelopment Corporation a certificate stating the amount of the additional Development Cost, if any. The additional amount as so determined shall thereafter be conclusive upon the Redevelopment Commission.