$\ce{Co^3+(aq) + e- → Co^2+(aq)}$ +1.81 V
$\ce{Mn^3+(aq) + e- → Mn^2+(aq)}$ +1.51 V
This is the data of Standard reducing potentials I have found on internet. Why is reducing potential of $\ce{Mn^3+}$ is less than that of $\ce{Co^3+}$. $\ce{Mn^3+}$ converts to $\ce{Mn^2+}$ which is half filled configuration and hence more stable. Am I missing something?