Using the principal values of the inverse trigonometric functions, the sum of the maximum and the minimum values of \( 16\left( (\sec^{-1} x)^{2} + (cosec^{-1} x)^{2} \right) \) is:
\( 31\pi^{2} \)
\( 24\pi^{2} \)
\( 18\pi^{2} \)
\( 22\pi^{2} \)