Mass. Gen. Laws ch. 40D § 11
If the proceeds of the bonds initially issued, by reason of increased construction costs or error in estimates or otherwise, shall be less than the amount required for the purpose for which such bonds are authorized, additional bonds may in like manner, and without any requirement of obtaining a certificate of convenience and necessity therefor, be issued by a municipality to provide the amount of such deficiency and shall be deemed to be of the same series and shall be entitled to payment from the same fund or funds as the bonds first issued without preference or priority of the bonds first issued. If the proceeds of the bonds initially issued shall exceed the amount so required, such excess shall be deposited to the credit of the sinking fund for such bonds.
Mass. Gen. Laws ch. 40D, § 11