From
TMF Associates MSS blog which is one of the links previously posted.
"Last week Inmarsat performed an analysis of pings received from other aircraft flying in the Indian Ocean region to confirm that this effect is consistent across all of these planes and therefore concluded that MH370 must have been to the south of the satellite at the time of the last ping, not to its north."
So, I think this in essence "calibrated" the data and the mathematical analysis.