The behavior of several relevant physical quantities calculated on the basis of coupled--channel wavefunctions are used in the study of fusion barrier distributions. The introduction of potential barriers modified by coupling effects makes possible the decoupling of the wave equations. This procedure leads to a view of the fusion barrier distributions that does not require to consider channels related to states which are admixtures of the ordinary ones. The ¹⁶O+¹⁴⁴Sm system has been selected as a paradigmatic case in the comparison between the theoretical and experimental data. For the sake of simplicity, the elastic and just an inelastic reaction channel are taken into account. The characteristics of the barrier distributions are analyzed on the basis of the modified potential barriers and the spatial behavior of physical quantities such as fusion rates, sources or sinks, and the incoming and outgoing currents in the different channels.