Wedding banquets are always like this. There is a charge for the wedding banquet in the hotel. I used to do the same thing at wedding banquets. Adding a seat is 500 yuan, because now many dishes are served on small plates, one for each person. If you occasionally add 1 seat to two tables of three, the hotel may not care too much. If you add two seats to each table, there will definitely be a charge. It is perfectly reasonable to charge everywhere.