Ayrprox
Maybe this will help; the 3 non-op days have always existed but have never been utilised, and you were told that they would never be called upon. Now that there is a need to use them, inorder for this to occur you get 4 days in lieu.
Down our way, those 3 non-op days have always been utilised and we have come to expect nothing less.
So why do you need 4 days in lieu as compensation to utilise the 3 non-op days?