Sec. 6. (a) Whenever the signature of an individual does not substantially conform with the signature of the registered voter with the name and address in the records of the county voter registration office, the signature is invalid and may not be certified.
(b) In determining whether a signature substantially conforms with a voter's signature in the records of the county voter registration office, the office must certify the signature if the office determines that lack of conformity may reasonably be attributed to the age, disability, or impairment of the voter.