Ships must not be full, or those offers would not be out there, Mark. If you are talking about the deals later in the year (for Asia/Australia), I did brief math, and could not see the benefit, given B2B bennies already built in, air credit for one since it is B2B, and SSS credits. I figure no F categories are available anyway, since ships sell from the bottom up.
Editing to say that unbelievably, we are all posting within minutes of each other!