In Scoville’s method, an exact weight of dried pepper is dissolved in alcohol to extract the heat components (capsinoids), then diluted in a solution of sugar water. Decreasing concentrations of the extracted capsinoids are given to a panel of five trained tasters, until a majority (at least three) can no longer detect the heat in a dilution. The heat level is based on this dilution, rated in multiples of 100 SHU.
Sweetness increases your tolerance for heat. The Scoville unit basically tells you how much sugar water it takes to mask the spiciness.
What?
Scoville is exactly how much water it takes to neutralize the capsaicin until you can’t detect it.
Which as different people have different tolerance it’s really not a precise method, and prone to mixed results for individuals.
It has nothing to do with sugar. Most people find sugar intensifies capsaicin
https://exoticchillies.com.au/scoville-scale/
Apologies, it seems that I am in fact mistaken.