I think when dealing with zero order the logic is different ie if you were to try a different logic to test;

a total order over all time

b orders after 21

c orders before 21

then in this a should = b+c

When you are looking at zero orders the same profile will have ordered zero before 21 and after 21..

I’m probably not explaining this very well but hope it helps.

Out of interest what was the purpose of creating these different segments?

Sean

Oh right, thanks! I get it now. Sometimes my logic messes up with me. Thank you so much, I totally get it now :)