If you actually used 20 grams of ordinary table salt (not Kosher salt), that amount would be around 3 1/2 level teaspoons. If you in fact used 2 rounded teaspoons, the percent relative to the flour should have been less than what I quoted when I converted your dough recipe to baker's percents.
I have a special scale that I sometimes use to weigh out small quantities of ingredients, especially lightweight ingredients for which either no conversion data is available or it is suspect. I use that scale (a MyWeigh 300-Z) mainly for converting teaspoons of ingredients to weights, as I did on several occasions recently to get conversion data to use in the various dough calculating tools Boy Hits Car and I have been working on. When making pizza dough for myself, I usually don't use that scale. I use the conversion data for the small quantities of ingredients, like yeast and salt, and for the flour and water I use my normal digital scale. I have found that the conversion data is quite close to what I would weight out on my MyWeigh 300-Z, so there isn't much to be gained from using the small scale. Accuracy also gets lost when using normal measuring spoons. I use level teaspoons but most people are likely to err on the high side by using rounded teaspoons. Or, if they are salt conscious, they might use scant teaspoons. Since we are eyeballing things, a lot of the accuracy gets lost. And not all measuring spoons are the same. Their designs can vary all over the place, so there is no guarantee of accuracy. Usually, the loss of accuracy and precision is not enough to materially throw off a recipe. If MWTC is able to tell us how much salt he used, and how he arrived at the amount, we might get clarity on the matter.