Business award seats (AAnytime vs Saver) are not the upgrade inventory. If you are looking or a business class upgrade, the inventory you need is C. General experience is that AA tends to hold the C on many/most routes (and especially HKG) until the days/day/hours before the flight.

There's further discussion of upgrades on both routes in these threads:

DFW: http://www.flyertalk.com/forum/ameri...ssion-139.html

LAX: http://www.flyertalk.com/forum/ameri...2016-a-45.html

Anecdotally in my experience: DFW has been difficult since the beginning. When LAX launched, I actually had an upgrade post a few months in advance, but that was before the route actually launched. Not sure if LAX is still possibly 'easier' (not saying easy) than DFW and/or if the addition of LAX has made DFW any less tough.