We show that a central characteristic of Super-X divertors, parallel area expansion fR (de ned as the ratio of the elementary area normal to the magnetic field at the target to that at the X-point, also known as total flux expansion), significantly changes the characteristics of the target plasma for fixed upstream conditions. To isolate the effect of parallel area expansion from other effects, we utilise SOLPS-5.0 simulations of an isolated slot divertor leg in a minimally complex, rectangular geometry. The grid is rotated outwards about the X-point in order to perform a scan in which only the parallel area expansion changes. We find that if the SOL remains in the attached, conduction-limited regime throughout the scan, the target electron density (temperature) scales approximately as f2R (1=f2R ), in good agreement with the modified two-point model presented in (Petrie T W et al 2013 Nucl. Fusion 53 113024). If, however, the SOL transitions from the sheath-limited regime to the conduction-limited regime during the scan, the simulated scalings of target electron temperature and density are weaker than predicted by the modified two-point model. The upstream density for transition from sheath- to conduction-limited regimes is found to scale approximately with 1=fR, in agreement with the modified two-point model. Assessing upstream-density-driven detachment onset, we find that the target electron temperature at which target density rollover occurs ( 0:6 eV) is independent of fR. Given this, the modified two-point model predicts a halving of the upstream (and target) densities at which rollover occurs when fR is doubled, in good agreement with the simulation results.