Fare amounts for a given fare will vary based on the estimated number of available seats at the time of booking and the number of passengers included in the booking. The “estimated number of available seats” is a projection as of the time of booking of how full a given flight and class will end up being. (It is different from the number of empty seats available at the time of booking.)
Flex, Saver, Special Saver, Round Trip Saver, JAL CARD Flex