Mountain Bear,
But you were looking through a tree in that example, and there are none between a 777 and the satellite.
The "ping time" in that example I think is also a time required to transmit a certain amount of data across your network, so you were measuring a data rate being slowed by the whirling tree, and not a time of flight/path length increased with time like Inmarsat were.
Inmarsat have many hundreds of thousands of flight records that they can test their method against. I'm sure they wouldn't broadcast faulty information.