I just booked an F award on the A380 -- all I signed on for was to see these defects in the website award tool. It popped up on a date that was good for me, I booked it, and sure enough the inventory now shows as gone. Excellent tool from my admittedly limited usage of it. I guess the routings shown depend on demand (route and season); the couple that I checked had pretty reasonable results, and there were F/J seats available for several different dates. Not every week, but not impossible either.