Welcome to Healing Well! Honestly, I think that your result is not all that uncommon Reflux can vary from day to day, hour to hour, and minute to minute. DeMeester scores can be very low on people who are bothered greatly by their GERD.
I was one of those. One time I got a score of 4, while my lungs were severely effected. Another time my score was 14.8 My PCP was tearing his hair out because he and my asthma doc both thought I needed the surgery, while my GI doc said no. My DeMeester was never really high, but my lungs were effected greatly. After four years of struggling with my GI doc, I was finally referred to a surgeon to explore the possibility of surgery.
What did your GI doc tell you about your results?
Good luck finding answers!