to this proceeding, which, notwithstanding section 12(b)(3) need not be extendable to 6 months, setting limits governing the timing and number of petitions filed for a particular registration or by a particular petitioner or real parties in interest, and defining the relation of a proceeding under this section to other proceedings concerning the mark. (e) Registrant’s evidence of use A registrant’s documentary evidence of use must be consistent with when a mark shall be deemed to be in use in commerce as defined in section 45, but shall not be limited in form to that of specimens as provided in section 1(a). (f) Excusable nonuse During an expungement proceeding, for a mark registered under section 44(e) or an extension of protection under section 66, the registrant may offer evidence showing that any nonuse is due to special circumstances that excuse such nonuse. In such a case, the examiner shall determine whether the facts demonstrate excusable nonuse and shall not find that the registration should be cancelled under subsection (g) for any good or service for which excusable nonuse is demonstrated. (g) Examiner’s decision