Do I need to pay extra for the price difference if I buy the ticket 29 days in advance?

If you purchase tickets in advance and have paid for them, it means that the purchase contract with the scenic spot has come into effect, so there is no need to pay the difference.
The price shown on the day of purchase is the amount. No need to pay. Tickets that need to be reserved must be paid.

If you purchase tickets in advance and have paid for them, it means that the purchase contract with the scenic spot has come into effect, so there is no need to pay the difference.
The price shown on the day of purchase is the amount. No need to pay. Tickets that need to be reserved must be paid.