Thanks, @David_Jerome and @PratheepArunRaj . Even though I remove the department dimension, the numbers still don't match up. Sorry I can't share the screenshot at that level. I also used Total Seconds Spent / (Visits - Bounces) to verify but got a different set of numbers. There could be some kind of conditions involved, like removing bots or outlier, or the system might use approximation to calculate. it's hard to understand.After all, shouldn't it be that the buckets of a metric has same cond...