Expression is showing null when selecting the Month field

[bhaveshp90]

Hello, 

The Expression Current-Dec POC is becoming null when selecting the Month field, without selecting it is showing correct values but when selected any month the expression becomes null.

My Expression for Current-Dec POC is 

Sum(POC)
-
Above(TOTAL Sum(POC), Num(Month))

Attached is the file for reference. 

thanks

Bhavesh

[bhaveshp90 · Accepted solution]

This expression is now working by adding MonthYear in the Set Analysis, thank you @sunny_talwar

Sum(POC)
-
Above(TOTAL Sum({<MonthYear>}POC), Num(Month))