Actually to throw another data point into the equation, I just used miles to upgrade a pretty popular transco route (thru IAH - peak travel times, too) and 3/4 segments were F9 at time of booking (6 weeks out). The last one cleared last night at the exact 30 day mark. FWIW.
I think your problem is that now you're looking only 2 weeks out and by that time CO has traditionally taken away the F seats.
[This message has been edited by jetsetter777 (edited 03-26-2002).]