Word of warning if you happen to use the PK75's via telephone(CSR): I had a multi-city trip on various days with some seating issues, so I used a CSR. I booked a party of four using four different PK certs.(must be booked separately ). My fare came to $835 with the PK, but a few days later my Visa was charged $935. Called back and was credited $100 (x 4), but she said it would show up on my next billing cycle. . I will see if interest is credited too.