Possibly this is a mis-reporting of a claim that location, speed and altitude could be derived from the pings by various analytical techniques.
It is also possible that the US Government has military capability that they do not want to talk about publicly. In other words, the data sent by Boeing is simple "I'm alive" data for non-subscribers to its service but that USA spy satellites intercept such data and store the location of the source on the fly. So Boeing doesn't know where the plane is or was but the military does, and its taken bureaucratic shuffling to get that data to the SAR people.