The robustness equality for the equilibrium classes $(2,n)$ and $(n,2)$

For the three-dimensional equilibrium classes indexed by pairs $(2,n)$ and $(n,2)$, let $\rho_{2,n}$ and $\rho_{n,2}$ denote their maximal full robustness, and let $\rho_n$ denote the corresponding robustness quantity. Bistatic-class robustness conjecture.

$$\rho_{2,n}=\rho_{n,2}=\rho_n.$$

The conjecture is motivated by the fact that the same solids maximizing the associated $S$- and $U$-robustness are expected to maximize overall robustness; the supplied text does not resolve it.