Conjectured crossing numbers for $K_{1,1,3,n}$ and $K_{2,4,n}$

Let $K_{a_1,a_2,a_3,n}$ denote the complete multipartite graph whose parts have sizes $a_1,a_2,a_3,n$, let $K_{2,4,n}$ denote the complete multipartite graph with parts of sizes $2$, $4$, and $n$, and let $cr(G)$ be the crossing number of a graph $G$. Let $Z(m,n)$ denote the Zarankiewicz expression

$$Z(m,n)=\left\lfloor\frac{m}{2}\right\rfloor\left\lfloor\frac{m-1}{2}\right\rfloor\left\lfloor\frac{n}{2}\right\rfloor\left\lfloor\frac{n-1}{2}\right\rfloor.$$

The crossing-number conjectures. For the relevant positive integer $n$,

$$cr(K_{1,1,3,n})=Z(5,n)+\left\lfloor\frac{3n}{2}\right\rfloor;$$ $$cr(K_{2,4,n})=Z(6,n)+2n.$$

These are proposed in the paper's conclusion as further crossing-number formulas; the source provides no resolution.