I don't know the pilot, never met him, and I don't wish bad things on people - but that option is still open for the CAA.
If you asked a representative sample of Qantas, Turboprop and GA piston pilots today to calculate an inflight Off-track PNR and CP ... how many would be capable of doing so in any amount of time, much less 5 minutes or so?
The ATPL exam requires such accuracy from the performance manual based tables, that ATPL methods aren't cockpit friendly.