In this study, we explored the influence of sodium configurations and site occupancy statistics within the cubic phase of Prussian Blue as a cathode material. Initially, we screened all potential sodium arrangements, focusing on symmetry-inequivalent structures, which were subsequently analyzed using density functional theory (DFT). This led to the identification of a novel, more stable sodium arrangement for the cubic Prussian Blue structure, which was validated through further DFT calculations. Notably, we found that purely electrostatic models (Ewald summation) fail to accurately represent sodium-sodium interactions within the cubic framework.