The Borough Planning Board or Board of Adjustment or governing body, as the case may be, shall make the rules governing such hearings. Any maps and documents for which approval is sought at a hearing shall be on file and available for public inspection at least 10 days before the date of the hearing during normal business hours in the office of the administrative officer. The applicant may produce other documents, records or testimony at the hearing to substantiate or clarify or supplement the previously filed maps and documents.