Blake777
Yes, if the radar echoes seen heading West were actually MH370 we have to consider that there was someone in control of the aircraft at that time. After that we can imagine that if someone was deliberately flying the aircraft until it ran out of fuel, with the idea that the aircraft would never be found, they would take a more westerly heading than the published tracks. However, if the pilots were incapacitated the aircraft could have flown on the autopilot towards WA. I was a 400 driver but, unless the 777 system is different, heading select is the only AP mode that I can think of that would work without pilot intervention, I do not know if this fits in with the tracks.
Basically, if I wanted to crash an aircraft without it being found I would crash it into an uninhabited island jungle rather than the sea. That way it would be hidden by the jungle and terrain rather than having bits floating all over the place.