I am very confused when I go to the combined tickets under admission charges on the official site I get the tickets for eur 36 (for 4 people). But when I want to book tickets it accepts seperate tickets for adults & children which comes to 55 eur. Why the difference? Should I buy tickets from the palace itself? Will there be a queue? We will visit on 30th sept, Sunday. Also I believe there is some trade fair in Vienna so will it be crowded?