A logic question about Karl's favorite brownie recipe

Question

I have been trying to solve the following problem:

Karl’s favorite brownie recipe uses semisweet chocolate, very little flour, and less than 1/4 cup sugar. He has four recipes: one French, one Swiss, one German, and one American. Each of the four has at least two of the qualities Karl wants in a brownie recipe. Exactly three use very little flour, exactly three use semisweet chocolate, and exactly three use less than 1/4 cup sugar. The Swiss and the German recipes use different kinds of chocolate. The American and the German recipes use the same amount of flour, but different kinds of chocolate. The French and the American recipes use the same amount of flour. The German and American recipes do not both use less than 1/4 cup sugar. Karl is very excited because one of these is his favorite recipe. Which one is it?

The following is my attempted solution:

From three of the statements given in the problem: "The Swiss and the German recipes use different kinds of chocolate.", "The American and the German recipes use the same amount of flour, but different kinds of chocolate.", and "Exactly three recipes use semisweet chocolate.", one can deduce that the German recipe does not use the semisweet chocolate because the German recipe uses different kind of chocolate from both the Swiss and the American recipes. Because each of the four recipes has at least two of the qualities Karl wants in a brownie recipe, it follows that the German recipe use both very little flour and less than 1/4 cup sugar.

From three of the statements given in the problem: "The American and the German recipes use the same amount of flour, but different kinds of chocolate.", "The French and the American recipes use the same amount of flour.", and "Exactly three recipes use very little flour.", one can deduce that the Swiss recipe does not use very little flour.

Because both the German and the Swiss recipe have only two of the qualities Karl wants for a brownie recipe, they both are not Karl's favorite recipe.

The statement "The German and American recipes do not both use less than 1/4 cup sugar." means the German recipe or the American recipe and not both uses less than 1/4 cup sugar. Because the German recipe uses both very little flour and less than 1/4 cup sugar, the American recipe does not use less than 1/4 cup sugar. It follows that the American recipe is not Karl's favorite.

Therefore, Karl's favorite recipe is the French recipe.

My questions are whether the statement "The German and American recipes do not both use less than 1/4 cup sugar." means the German recipe or the American recipe and not both uses less than 1/4 cup sugar and whether the statement "The German and American recipes do not both use less than 1/4 cup sugar." is equivalent to the statement "Both the German and the American recipes do not use less than 1/4 cup sugar." or not?

The question is from the book: Daepp, U., & Gorkin, P. (2011). Reading, writing, and proving: A closer look at mathematics. In Reading, writing, and proving: A closer look at mathematics (2nd ed., p. 31). New York: Springer.

Answer 1

On its own,

"The German and American recipes do not both use less than 1/4 cup sugar."

means that one or two of them use too much sugar.

But you are also told "exactly three use less than 1/4 cup sugar" so in this question only one can use too much sugar.