Here is my formula
IF [AbnormalFlags] ='' AND [Cotinine]='NEGATIVE' THEN [AbnormalFlags]='N'
ELSEIF [AbnormalFlags] = '' AND [Cotinine] = 'POSITIVE' THEN [AbnormalFlags] = 'A'
ELSE [AbnormalFlags]
ENDIF
It appears to be like it is working as expected in the Preview window

But in the Output it is generating 0's instead of the value
Here is the data flowing into the formula tool

Here is the data flowing out of the formula tool

It should be showing N not 0
What am I doing incorrectly?