Grade table add points error in exam class

Question

In the exam class, I would like to assign points to both the question and the parts of that question. But when generating the grade tables, the points for that question will be two times of the correct value since it adds both the points for question and the parts therein.

Below is a MWE:

\documentclass[12pt, addpoints]{exam}

\begin{document}
\begin{questions}
\question[10]
Why is there air?
\question[10]
What if there were no air?
\begin{parts}
\part[5]
Describe the effect on the balloon industry.
\part[5]
Describe the effect on the aircraft industry.
\end{parts}
\question[20]
\begin{parts}
\part
Define the universe. Give three examples.
\part
If the universe were to end, how would you know?
\end{parts}
\end{questions}

\begin{center}
\combinedgradetable[v][questions]
\end{center}

\end{document}

Answer 1

Instead of giving the total points at the top of the questions you can use the command \droptotalpoints to show the total points of that question at the end of the question.

\documentclass[12pt, addpoints]{exam}

\begin{document}

\begin{questions}
\question[10]
    Why is there air?
\question
    What if there were no air?
    \begin{parts}
        \part[5] Describe the effect on the balloon industry.
        \part[5] Describe the effect on the aircraft industry.
    \end{parts}

\droptotalpoints

\question[20]
\begin{parts}
    \part Define the universe. Give three examples.
    \part If the universe were to end, how would you know?
\end{parts}

\end{questions}

\begin{center}
\combinedgradetable[v][questions]
\end{center}

\end{document}