Michael, sure, they were probably all familar with the 1000 km for 1960. But, at the time, a couple of days after the 2004 quake, the magnitude for the Sumatra quake was somewhere between 9.0 and 9.3 and so the 700 km or whatever they thought it was seemed most likely, compared to 1000 km for a M9.5. There were some inversions that showed the smaller fault size...and there was not very much slip on the northern parts of the fault (I don't know what the latest thinking is).
Chris