MH370 Had a Satellite Phone: New information

I had mentioned in previous MH370 posts that I'd like to know more about what, if any, satellite phones the Boeing 777-200ER airplane carried, and whether there's any evidence of use during the flight. (A satellite phone looks something like a large cellphone, but it relies on satellites rather than cell towers, so a satellite phone is usable worldwide, whether you're calling from mountaintop, ocean, or desert.) 

This obscure subject never got attention from commentators discussing the many mysteries of the flight; rather, the TV air time focused on ACARS messages, speculation about possible cellphone use by passengers if hijacked, and eventually got around to the satellite pings revealed by Inmarsat. 

Of those, Inmarsat's "hand-shake satellite pings" provide the best info we have about the last hours of flight, if sketchy:

Now, we have some glimmerings that go beyond the ping question. Buried in the otherwise tedious 47-page report from Inmarsat listing many hundreds of signals is a page showing satellite-phone log entries. (For those who have had trouble locating the full ping log, here it is.)

Page 40 shows two attempts from the ground to telephone the aircraft, using Inmarsat's satellite-phone service. The first call to MH370 came at 18:39 Coordinated Universal Time, or UTC, or 2:39 am Malaysia Time, and the second came at 23:13 UTC, or 07:13 am Malaysia Time. 

Here's the page:

What's it mean? Maybe not much, but when the mystery is so opaque, just about anything can be interesting. Even the Wikipedia page on MH370 doesn't reference the satellite-phone info.

A few points:

• Note that the two calls are shown as "not answered," rather than "terminal unreachable." From a lengthy discussion about the ping log on the DuncanSteel website, that suggests the satellite phone had power from the airplane's main circuits; it rang for an extended period; but no one picked up the phone.
• I feel confident that the calls were directed at a hard-mounted satellite phone intended for priority uses by the crew, rather than a mobile sat-phone carried by a passenger, or one provided for passenger use by the airline. (Note that Malaysia Airlines does advertise that satellite phones are available for business class travelers on this type of airplane, the Boeing 777-200.) 
• Finally: we are left to guess that the only sat-phone calls made to or from MH370 are the two attempts cited in the log, but we don't know that for sure.

There's solid information from the ping log that the airplane spent another hour in the air following the second call. The airplane then experienced a temporary power failure as the fuel supply ran out. 

All these bits of evidence lead me to think that after a couple of months' pause, the next deep-diving autonomous-submarine searches will center where they should have been all along, the southern terminus of the most likely flight path (graphic by Reuters):