Hi Tony, glad to see you are working on Chicago crime! I'm from Chicago originally but love the weather a whole lot better down here in the ATL. Can you post your workbook so we can understand the problem better?
I was expecting to see a difference but I couldn't post my actual file because it has over 3M records. So I created a skinny version and posted it. I noticed that it was working like I expected with slight variations in years from the little look up file I created from census data. I went back and removed all of my data sources and brought them back and rejoined them. Low and behold it calculates correctly now.
So I guess I learned:
1. Try recreating the problem with a smaller data set to see if it persists
2. This forum is moderated well and other people want to help
Have a great day!