It does, but powder is not liquid,so 1 tablespoon of powder isn't gonna weigh 1/2 ounce.
i wonder if his jar is by volume and says 3.5 oz on it cause he said 100g / 3.5 oz
100 grams = 3.5 ounces, that is understood, but most people don't have food scales, and one tablespoon of most powders doesn't have the same density as water, so they will weigh less.