Personally I think the BN number is by far the fairest way of determining upgrades, if your really committed to getting the upgrade then your going to hovering over your computer or phone 48 hours prior to departure, at least every one used to know the importance of getting that magical BN001, the new CIV score if its anything like BA's system is going to create a maelstrom of discontent, as the far from reliable CIV algorithm creates a level of distrust and suspicion amongst fellow tier members, a least we used to know where we all stood before... Like BA will CX Gold Card holders be upgraded over diamonds to encourage travel?