Speaking to friends who have sampled more than just the CX training system, it appears that CX does have a very high standard. BUT, how they set about achieving it is the problem.
Many years ago in QF, just after they had absorbed Australian Airlines(short haul), the long haul fleet had 100% failure rate on commands. They thought the short haul fleet was being slack as they had near 100% pass rate - did I forget to mention that the command course was 9 months long on QF mainline!
We all make mistakes. Thats why we have a PM. Being flawless for 4 months is possible but difficult. Maybe the checkers and trainers have forgotten what it was like to do command course - the self induced stress far greater than anything CX can throw at you!
A mature organisation looks outside itself and asks why other airlines have higher pass rates. A mature organisation seeks best industry practice. But then we don't even manage boeings the way boeing suggest. What did someone post ....we invented aviation here;-)