Originally Posted by
slats11
Or perhaps was already very low altitude in order to assess sea conditions when fuel exhausted, and ditching only a few km further on.
The whole thing is apparently irrational and an assumption of fuel exhaustion is just that, an assumption.
The same effect would be achieved by manoeuvring for ditching while still retaining power for ditching. That alone would account for not travelling as far south.
Professor Mishar Dohler* opined right at the outset that the final ping could have been as the aircraft sank.
*
King's College London - Professor Mischa Dohler