Partite-set comparison conjecture for expected propagation times of complete bipartite graphs

Let $K_{m,n}$ have partite vertex sets $R$ and $R'$ of orders $m$ and $n$ respectively, and let $u\in R$ and $v\in R'$. Partite-set comparison conjecture. If $n>3$ and $m<n$, then

$$\operatorname{ept}(K_{m,n},\{u\})>\operatorname{ept}(K_{m,n},\{v\}).$$

The conjecture asserts that, except for the noted small outlier, starting from a vertex in the larger partite set gives a smaller expected propagation time. Its status is not established in the supplied material.