Abstract : We study the effect of increasing the model parameters (e.g. arrival rates and traffic intensities) in the Erlang blocking model with heterogenous user requirements. First-order (monotonicity) and second-order (concavity) qualitative results are obtained for the performance measures of interest (loss probabilities, throughput, channel occupancy, etc.) both in the transient and in the steady-state case. Stochastic and likelihood-ratio orderings together with coupling techniques are used to indicate the effect of modifying the model parameters.