We obtain a phenomenologically acceptable PMNS matrix in a flipped SU(5) model, possessing the Z(4R) discrete symmetry, from the compactification of heterotic string E-8 x E'(8). To analyze the Jarlskog determinant efficiently, we include the simple Kim-Seo form for the Pontecorbo-Maki-Nakagawa-Sakata matrix. We also noted that vertical bar delta(PMNS)vertical bar less than or similar to 63 degrees for the normal hierarchy of neutrino masses with the PDG book parametrization. (c) 2019 The Author(s). Published by Elsevier B.V.