Whoever is in command of the investigation does have far more information than they are providing the press with.
If they were able to give us arcs for the last ping, they can do the same for all the other pings. By tracing those arcs, using satellite timestamps to calculate the time between each ping, wind data and calculated GS, it shouldn't be that difficult to calculate several possible routes for the aircraft, and then "precise" search areas...
I'm just a poor ground ops specialist, I suppose they have far better people working on it, but if I came out with that possibility, why wouldn't they? So yes, I suppose they have a good idea of the areas where to look...