The petitioners for a hearing pursuant to the provisions of N.H. Rev. Stat. § 482:79 shall make a deposit to the department of $100 with each such petition. This payment shall be for expenses of publication, mailing, and posting of notices by the department and for the expenses of hiring a hearing site if necessary for hearings held during normal business hours in Concord. For hearings held outside of Concord or after normal business hours or both, the payment shall also cover expenses of the hearing personnel including per diems for personnel of the department. If said expenses amount to more than $100, the department shall require the petitioners to pay the additional amount before it renders its decision.