In the event that any such city or county fails to pay the amount fixed and ascertained by the report of the body determining just compensation, as directed by the court and within the time, or any extension thereof, allowed by the court as provided by § 15.2-1912, the proceedings shall be dismissed on motion of any party thereto. If such proceedings be so dismissed, judgment shall be entered against such city or county for all costs and the attorneys’ fee or fees actually incurred by the defendant or defendants; provided, however, that the fee or fees shall be so paid only to the extent they are reasonable in the opinion of the court.