Fare Calculation Rules

The fare basis changes depending on the date of purchase, the date a change was made, or similar.

Here are several examples demonstrating fare calculation rules and fare basis date.

On the purchase date, the fare valid on the start date of your trip will be applied. (The booking class and seasonality of each flight will apply to the outbound and return flight boarding dates.)
A Flex round trip is purchased on 4/5, with an outbound part (4/10, ANA51, Haneda to Chitose) and an inbound part (4/30, ANA58, Chitose to Haneda).

Even if a price increase is subsequently made on 4/12 to the fare amounts for April flights, the inbound fare amount will not be changed, as both the outbound and inbound fare amounts valid for the start date of the trip (4/10) on the ticketing date (4/5) will be applied.

On the change date, the fare valid on the start date of the trip will be applied to the entire itinerary. (The booking class and seasonality of each flight will apply to the outbound and return flight boarding dates.)
A Flex round trip is purchased on 5/25, with an outbound part (7/1, ANA 253, Tokyo/Haneda to Fukuoka) and an inbound part (10/3, ANA 258, Fukuoka to Tokyo/Haneda).

If changes are made to the reserved flights for the outbound (7/3, ANA 253, Tokyo/Haneda to Fukuoka) and inbound (10/4, ANA 258, Fukuoka to Tokyo/Haneda) parts on 7/1, the fare amounts valid for the start date of the trip on the day that the changes are made (= 7/1) will be applied for both parts.

On the purchase date, the fare amount valid on the start date of the trip will be applied to the sector that is being changed. (The booking class and seasonality of each flight will apply to the outbound and return flight boarding dates.)
A Flex round trip is purchased on 5/25, with an outbound part (7/1, ANA 253, Tokyo/Haneda to Fukuoka) and an inbound part (10/3, ANA 258, Fukuoka to Tokyo/Haneda).

After boarding the outbound flight on 7/1, if changes are made to the reserved flight for the inbound part (10/4, ANA 258, Fukuoka to Tokyo/Haneda) on 7/3, the fare amount valid for the start date of the trip (7/1) on the purchase date (5/25) will be applied to the inbound part.

(Q) Flight tickets that permit reservation change are priced different depending on the travel date (period). If there is a difference between the original fare and new fare, will the difference be charged or refunded?

(A) The fare amount applied depends on the timing of the purchase or the timing of the change, etc.
Please see above for further details.

(Q) Where can I find out if fare amounts have changed?

(A) Whether fare amounts have been changed can be checked at information on Fare Setting/Changes.