For some things, such as how many tomatoes you use in salsa, exactness doesn't really matter (and Wiki isn't terribly authoritative!).
And, Germans aren't so terribly exact in their recipes either. "Enough flour until it's firm enough" (badly translated out of my memory from various German bread-type recipes). Or look at the recipes from your grandmother/great grandmother.
wie hart oder weich, kann das gleiche Gewicht Tomaten ein ganz unterschiedliches Volumenmaß ergeben.
I believe that I said I'd rather use penguin's second source, "about 3 pounds of fresh tomatoes makes 1 qt of canned tomatoes" than the former. No German recipe can determine how ripe etc. the tomatoes are either (or specify what they mean by "ripe" tomatoes). That's always subjective.
Get over it. Somehow, many people in the US manage to cook well given such recipes. And, somehow, many Germans manage to cook well with the non-exact recipes here.