These frequency shifts range from an increase of about 325Hz to a decrease of about 750Hz. I will say this: the Inmarsat people must be very good engineers to detect such small changes in a 1600MHz carrier, particularly when their radio equipment was probably designed to overcome and ignore such noise.
The official explanation does not have to be strictly true. It probably only has to be plausible.
I hope and believe there is indeed independent evidence used to refine the Inmarsat data. If so then I believe we will eventually find the aircraft.
It would seem strange if 7 or 8 pings were heard by a satellite in ego orbit, and not one was heard by other satellites designed specifically to pick up faint signals. Particularly given the pings were coming from a fairly quiet location (mid-ocean), but from a general area (mid east and Pakistan) covered by plenty of satellites.
Would it be possible that people were even looking for the aircraft towards the end of its flight when they knew it was missing?