Counting Unique Values in Header

I am able to get my graph to count unique orders for each subscription type, but then when I try to create a header to show a total of Unique Orders and Revenue, it returns a value of 1 (should be 26, if you add the total orders from each column up). 


My Beastmode for Total Unique Orders is: COUNT(DISTINCT `ah_id`)


Beastmode for the header (adding the unique orders and showing total revenue) is: CONCAT(COUNT(DISTINCT 'ah_id'), ' Memberships, $ ', ROUND(SUM(`cost`), 0), ' Revenue ')