For what it is worth in this debate, I have recently had to take up sim training when my medical went sarfff....and I am quite frequently picking younger guys up after I have cleared them to FL60 when they check in "climbing 6000". Altimetry and strict adherance to its conventions was drummed into me in the air force but, clearly, similar emphasis is being missed somewhere along the way. You simply have to be an absolute pedant when it comes to altimetry.....