Let $X$ be a Spherical variety for a reductive group $G$ with a Borel subgroup $B$. A boundary divisor of $X$ is a $G$-invariant divisor and a color of $X$ is a $B$-invariant divisor which is no $G$-invariant. We can also assume that $X$ smooth and the divisor given by the union of the boundary divisors is simple normal crossing.

Does there exist a formula (in terms of invariants of $G$, $B$ and $X$) for the number of boundary divisors and colors of $X$?