Airlines try to have the exact number of meals that is needed, and no more. Sometimes when I buy a last minute ticket, my boarding pass reads, "meal service may not be available" even though it is a meal flight. This is because catering stocks only the meals it needs.
All the more so for premium cabins. This is why your choice of meal (in F) may not be available.
[This message has been edited by zrs70 (edited 01-30-2001).]