Also, ANA doesn't offer every open seat for award booking, and will often let a premium cabin go out empty. This has been mentioned repeatedly earlier in the thread.

Several of us have found one award seat available in F, booked it, and flown in an otherwise empty F cabin.

Some Japanese bloggers have hypothesized a quota of only 1 F and 2 C seats for each long-haul flight, with some additional availability for high-level ANA members. I'm not sure whether this is accurate but it matches my personal experience.