Section 6. The directors of an industrial development financing authority shall serve without compensation as such but each director shall be reimbursed for all necessary travel and other expenses incurred by him in the discharge of his official duties. The compensation of the executive director shall be subject to review and approval by the Massachusetts office of business development. Such compensation, if any, and expenses shall be allocated by the authority among its various projects, in such manner and amounts as it deems proper and shall constitute current expenses thereof.