Originally Posted by
epigram
Could it be that the booking at the F mixed award rate only works if one of the flights does not operate F at all?
If all the flights operate F but do not have availability in F, you can't make a mixed booking? Instead you need separate bookings?
that is my read of the situation.
Fare filing is complex, but what SQ means is if you are trying to booking ZRH-SIN-BKK in F where SIN-BKK does not operate F, they will allow you the F fare for the entire journey.
However, in SIN-FRA-JFK example, because all segments operate with F cabin, then they are unable to book you in J even if it is of your voluntary accord because the system is unable to price such an itinerary.