When the administrative law judge determines that a final order cannot reasonably be issued within 60 days after the date on which the hearing is finally closed, the administrative law judge shall announce, at the conclusion of the hearing, that the time for a final order will be extended. The proposal for decision shall include a reference to the announced extension. The extension shall be for a period extending at least 45 days after the issuance of the proposal for decision to ensure enough time for the filing of exceptions and replies. A longer extension shall be granted in matters of unusual complexity.