The Scoville Scale measures how much do you have to dilute something spicy before testers can no longer detect the heat. Did you have to dilute it 10-fold? That's 10 Scovilles. 1,000-fold? 1,000 Scovilles. Easy enough.
You might expect that a hot sauce which is 10% 200,000 Scoville peppers, and 90% not-hot ingredients would be 20,000 Scovilles. And you would be right! But the label will say 200,000 Scovilles.
Hot sauces are typically marketed as the Scoville rating of the hottest ingredient, ignoring the fact that these peppers are heavily diluted by not-hot ingredients. Both companies and consumers want a big number on the label that secretly doesn't contain much of the expensive and painful pepper.