Even if your premise about two sources were correct, which is merely your own opinion and not fact, the Inmarsat data and the Malaysian reporting of last known position are mutually supporting data. The LNP itself is supported by the fact that it lies approximately 240 miles from the radar antenna on Pulu Penang: exactly where we would expect the horizon to block a conventional radar signal. So we have verifiable data to work from.
@ propduffer.
The standard procedure of two independent sources is neither opinion, nor fact. It is an established procedure in professional investigations worldwide, used by law enforcement as well as by serious journalism.
That Inmarsat data and Malaysian primary radar reports are mutually supporting, is a fallacy. Under the premises of any serious investigation, if these informations were not given independently and practically simultaneously, verifiably not knowing of each other, then that means nothing, since the later publication could have been influenced by the first. I'm not saying that was the case. Just keeping a cool rational mind.
Conclusion: we have no verifiable data to work from, after the loss of secondary radar return after IGARI. We have some data to work with, which we must ASSUME to be accurate, but can't verify.