德明的解释是正确的。按照教育部的条例，如果第一志愿是WL但未被录取，第二志愿将成为第一志愿。也就是说，一旦德明没有录取，您的孩子将自动被四德录取。
教育部的详细解释如下：
I have received two offers, a Waiting List (WL) Offer from School A (my preferred school) and a Confirmed Offer (CO) from School B. Would putting School A as my first choice and School B as my second choice affect my chances with School B should I not be allocated School A?
Should I put School B as my first choice, since I am guaranteed a place there?
Assuming you are eligible for an academic course that School A and School B offer:
You put School A as 1st choice, followed by School B. If School A has enough remaining DSA-Sec places to admit you after the other students given COs have made their choices, you will be allocated School A.
You put School A as 1st choice, followed by School B. If School A does not have enough DSA-Sec places to admit you after the other students given COs have made their choices, you will be allocated School B since you have a CO from School B.
You put School B as 1st choice, followed by School A. Since School B is your first choice and School B has given you a CO, you will be posted to School B. You will not be allocated School A, even if School A has enough DSA-Sec places.