I have to ask the same as GvonSprout:
are those pings attributable to an individual source? Yes or no. And I would bet that this was the very first question to Inmarsat. And if they said yes the follow-up question was "prove it".
The rather random course plotted in a graph earlier could also just be the coincidential return of 'pings' from other aicraft systems doing the same at an expected location.
So the question remains, same ping for all or individual pings?