On the Total Positivity of Contingency Metamatrices

M. Kapranov and V. Schechtman introduced the contingency metamatrix for a finite Coxeter group and conjectured that the contingency metamatrix is totally positive. For the Coxeter groups of type $A$, this conjecture has been proved by P. Etingof. In this article, we prove this conjecture for the Coxeter groups of type $B$ and exceptional types.