We calculate the next-to-next-to-leading order (NNLO) contributions in the epsilon expansion with a small imaginary chemical potential and discuss their relevance to Dirac eigenvalue correlators. We show how to minimize systematic deviations from random-matrix theory by an optimal choice of lattice geometry in the case of two light quark flavors. Finally, we determine the low-energy constants Sigma and F from configurations of JLQCD with two dynamical overlap fermions.