For good cause, the commissioner may extend the time within which a taxpayer is required to file a return, and if such return is filed during the period of extension no penalty may be imposed for failure to file the return at the time required by this chapter, but the taxpayer shall be liable for interest and late payment charges as prescribed in N.H. Rev. Stat. § 21-J:28, 32, or 33. Failure to file the return within the period of extension shall void the extension.