The Parties may, if they think fit, enter into an Agreement in Writing, which shall not be subject to any Stamp Duty, and which shall be embodied in the said or any subsequent Order, that upon the Finding of the Jury in the affirmative or negative of such Issue or Issues, a Sum of Money fixed by the Parties, or to be ascertained by the Jury upon a Question inserted in the Issue for that Purpose, shall be paid by One of such Parties to the other of them, either with or without the Costs of the Action.