Then you will be able to use the balance for your tickets. When the reservation is checked in it will basically be putting a credit on your reservation which would be for your room and tax and then the extra that you paid above that. Make sure when you purchase tour ticket you let them know that you overpaid the room and tax and should have some left over (as room and tax does not actualy post until date roll) so that the CM realizes that, since tickets need to be paid for upon purchase they can figure out how much of the money if for R&T and what is left over for incidentals.