I knew this subject was complicated, but not THIS complicated!
But it isn't - that's the point.
Counting movements, and recording which runway they used, and why, is hardly rocket science. I don't believe for a moment that NATS aren't doing that part properly.
Yet the CAA, in their progress report on the trial, talk about "discrepancies in the published figures" and "queries on the consistency of the data", together with a pointed reminder to all concerned that the trial needs to produce data "sufficient to generate a robust information-base on which Government can ultimately take decisions".
I can see the CAA's point, though - for example the stats would have us believe that 100% of last Monday's movements were easterlies, when in fact the whole day was westerlies.