Parameter-varying stage costs are considered throughout this note. An Economic Model Predictive Control algorithm (EMPC) is proposed and analyzed to cope with possible feasibility issues in the on-line optimization phase due to sudden commutations of terminal ingredients as resulting from the variation of the cost functional. Asymptotic average performance bounds are obtained in terms of weighted averages of performance at equilibrium states and along reconciling trajectories joining such equilibria. A simulated example illustrates the approach.