Hi feb,
of cos you have to pay for those tables that you have confirmed with Agnes, but did not "open" during the dinner... and since you have already paid for the food, the option is to either distribute the food among the other tables or you can arrange to pack the dry stuff home..
if you have confirmed 25 tables, and oriental gives you two spare tables, and you only managed to use 25 tables.. you do not need to pay for the 2 spare tables..
hope i clarify your doubts and not make u more confused...