Why is the Conductivity trend same in fused and in dissolved or aqueous state of ionic compounds?

For an example if we take $\ce{KCl}$ and $\ce{NaCl}$ then I have understood the part where in aqueous state $\ce{Na+}$ becomes bigger than $\ce{K+}$ hence the conductivity reverses but in fused state ions exist on their own hence the conductivity order must remain $\ce{Na+} \gt \ce{K+}$


