I am in correspondance with Professor Bauduin from Brussels University, Project Manager for the Besix Design Department.
He now refuses to post on this forum because of mis-interpretation and ambivolent responses to his messages! (Thank you Fury for forwarding him to me)
He has direct contact with the Besix site HQ too for the updates.
The final height will be measured from the datum point at the top of the concrete raft foundation, where construction started.
The 'official' heights reported elswhere recently are actually correct, but is a plot to decieve because the height from the sensors at concourse level are the ones presented.
Heights are adjusted by the 15.4m difference.
This is EMAAR's way of giving the height a final unexpected boost when it comes to world record day when it tops out!