On top of the saving on the airline prices, I think booking early may still get the best price for ABD too. We were thinking of planning an ABD trip for this summer but ended up making other plans. However, I have been watching several trips since the dates were released for 2012 and the price of the trips has increased enough (and in come cases more than) the $300/ trip that you will save with this offer. So you have to factor in that while some offers come out later, the price for many dates has increased in the meantime.
I kept an eye on the trips to get a feel for what to do if we want to book one for 2013 or 2014 and based on what I have seen, I think booking when the dates are released is the way to go (and hopefully combine that with a TA early booking incentive.)