Custom Column not working

Hi all, 

Please assist whats wrong with below. It doesn't seem to filter properly. 

Table.AddColumn(#"Added Conditional Column", "Dupli", each if [Count]>1 and [LODT]="null" and [DCHT]="null" then "YES" else "NO")

I've already tried >1 / ="2" / =2 / but still all data in that column shows NO even though there are thousands that should have YES value. 

In DAX, I have successfully created it as below but I need to create the columns directly in power query to filter the duplicates out.
 

Thank you.


Regards,

Dina