hamster3null - have you tried to factor in the winds aloft into your calculations? They seem to be considerable that night (and would of course affect the ground speed at each point). The problem with "crowd computing" is not having all the best information published.
This link was mentioned a while back and is the only place I've seen that attempts to show winds aloft at that time:
Investigation of a possible "southern arc" contrail from Malaysia Flight 370 - 8 March 2014 - Weather Graphics
If needed, I bet Tim Vasquez at Weather Graphics could get them for the altitudes and locations of interest.