(c) Discovery of other affected parties. Notwithstanding the provisions of
paragraph (a) of this section, if the plan administrator discovers additional persons entitled to a notice of plan benefits after the expiration of the time period specified in
paragraph (a) of this section, the failure to issue a notice of plan benefits to such persons within the specified time period will not cause such notices to be untimely under
paragraph (a) of this section if the plan administrator could not reasonably have been expected to know of the additional persons and if he or she promptly issues, to each such additional person, a notice of plan benefits in the form and containing the information specified in
§ 4041.23.