My experience has not been good so far....
I made a reservation for ZRH-NRT (economiy flex) for my wife and my daughter for Monday, 29 September and duly paid an ASR fee (CHF 99 per person if I remember well), the seat was booked accordingly.
I had to re-book the flight and to advance it by one day, i.e. on Sunday, 28 September.
The travel agent (Amex) mentioned that the ASR would be valid also on the new flight. Now it turns out that the ASR is worthless as Swiss blocks the reservation as soon as 75% of the seats are sold. I will have to see what reservation I can make during the web check-in.
It also looks like the money for the ASR is down the drain....
The ASR turns out to a rip-off for customers like me, who end up paying twice for flexibility: (i) the ticket price is very much higher if you want a flexible ticket and (ii) you risk losing the ASR fee.
Regards,
Adrian