To put this hypothesis to bed. The satellite has a footprint that covers approximately one third of the Earth's surface. Even though there are lots of empty spaces in the southern Indian Ocean, this satellite also covers a lot of Africa, India, most of Russia and most of Europe. These are not silent areas, there are lots of transmissions to 'listen' to. The only way the satellite can discriminate between 'pings' from aircraft is that these low level protocol 'pings' are actually short messages with a unique 'electronic aircraft address'. It is the INMARSAT business to ensure that these thousands of aircraft transmissions are not mixed up. So the hypothesis that they 'tracked the wrong plane' is just not supportable.
For starters, the satellite doesn't discriminate between anything. It's just a bent pipe retransmitting what it hears in an analogue sense. All demodulation and interpretation occurs on earth.
An end point in such a network would be identified by a DNIC or number, something that looks like an international phone number or an x.25 address. It certainly isn't identified by an aircraft manufacturer's serial number. If the data service isn't paid up and active (there was an early post in this thread indicating the airline didn't use the inmarsat service) who cares about keeping this number-to-plane mapping in sync. Or who cares if the non-useful bit of kit is removed for testing etc.
If the service was not paid up, there would be no polling from the network towards the terminal. There may be polling from the terminal towards the network "->can I logon"...."<-no"... Unless there is a two way flow from the network to the terminal and back to the network timing is going to be very hard to establish. That the range ring lay exactly on the 40 degree contour is telling of the precision the author felt they had. This wasn't 41.5deg, or 42deg, it was more like vaguely in the vicinity of 40deg.
That the inmarsat range calculations were calibrated by the "known" location of the aircraft pre-disappearance is also troublesome. A vague range ring drawn through the place the sat terminal was assumed to be.
Look, I'm accepting that this hypothesis can go right out the window if a few bits of information (like it being and inactive sat service) turn out to be incorrect. There might also be non-public information clearly discrediting this theory. But to me, fire causes loss of comms, then loss of control sounds more plausible than deliberately evades radars to end up in the southern ocean.