(c) If there are no seats available in the economy class when a booking is made a member may upgrade to the business class upon payment of the cost of the additional airfare. The member may then claim 80% of the additional payment back from the Secretary to Parliament (Secretary). The airline or travel bureau concerned must certify that the economy class was fully booked. A maximum of 4 single air journeys of the combined total quota per financial year of a member and her/his spouse or companion and the other registered persons who are entitled to travel facilities, may be used for this purpose.