We consider the consequences of keeping the total surface fixed for a polydisperse system of N hard spheres. In contrast with a similar model [J. Zhang , J. Chem. Phys. 110, 5318 (1999)], the Percus-Yevick and Mansoori equations of state work very well and do not show a breakdown. For high pressure Monte Carlo simulation we show three mechanically stable polydisperse crystals with either a unimodal or bimodal particle-size distribution.