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