Add/Subtract Quiz Totals on Results Slide

I'm stumped and I need your help! I have created a "Counter" variable to add when a learner clicks on the "Normal" state (which is set up to show an answer hint). Each question is valued at 10 for a correct answer, 0 for an incorrect answer, and 1 for using the hint. The counter appears to be working.

Now, let's use an example of 10 questions, where I get 8 right and used 2 hints. The total should come to 78 (8 correct answers minus 2 hints). 

I set up a variable on the Results slide to subtract "Counter" from the Quiz Score. But it's not working. 

It's not subtracting -- it's showing 80 (8 correct answers), which ignores the counter. What am I missing?