What I see missing in this expression is you haven't ignored the selected fields of master cal.
Meaning if you have selected Year then it will calculate the expression correctly, but by default the Identifier is the current selection. So the expression will try to evaluate with in the selection you have made, and that's where the conflict happens and you get 0 as result.
So it is important that you ignore the Year selection in set analysis. Something like below.
Hope this helps.