The suggestions posted here did not work for me. Maybe it's because of updates to Storyline since the suggestions were made. (This thread is several years old).
I did figure out a fix, and I'm posting incase it can help someone.
I added a GRADED question rather than a SURVEY question. I added it to the beginning and set the score for the correct answer to 100. I created a trigger to auto populate the score as discussed here and I also hid the page with the triggers as discussed here - but since it's graded, I had to add the triggers to the Correct feedback layer as well. When it runs, the screen flashes, so I added a white rectangle to go over the entire slide to hide the content. In the attached sample, I made it semi-transparent so you can see what I did.
For each of the questions, I scored the incorrect answer with negative points and correct answers with 0 points.
Prior to realizing that my course would not report my scores to the LMS correctly, I had created variable (TotalScore) to show a score at the top of the page that decreased with each incorrect answer. For each question I had a variable that subtracted from the Total Score. I kept those variable, but they possibly could have been done with some built in triggers - not sure.
I displayed the Total Score variable on the results slide in addition to the percentages shown by default on the results slide.