Quantum mechanical calculations on three potential energy surfaces for the prototype ion-molecule reaction He + H-2(+) --> HeH+ + H have been performed in order to test the influence of their accuracies on reaction probabilities and cross sections. The ab initio points of McLaughlin and Thompson (1979) fitted by two different functional forms, and a fit of a new set of ab initio points have been used. Dynamical results, in particular the rich resonance pattern, illustrate the dependence both on the nature of the potential energy surface, and on the type of functional form used to fit the same ab initio data.