Hi Karen,
It is possible that only one child was born in Ludwigsburg, and other children were born somewhere else. Since Wilhelm Leonhard Friedrich Matthes was a citizen of Langenburg (Dekanat Blaufelden), and Auguste Catharine Louise Hiller was from Kirchberg (Dekanat Blaufelden), you might find other birth entries there. However, they could also have moved to a completely different place.
Good luck
Angelika