Top panels: time evolution of the neutron exposure for the parametrized s-process calculation and the neutron sink approach with different cross-section values for a composition of heavy elements (A > 30), corresponding to a solar abundance pattern scaled down to Z = 10^-8. The abundance values for light elements (A < 30) were taken from stellar models calculated using GARSTEC except for , where we take two different values. Panel a) shows results for a mass-fraction of 10^-4 and panel b) for a mass-fraction of 10^-2. In both cases, lines depicting results for the full network (black line) and a sink element (cyan and red lines) overlap. To enhance differences for each value of the abundance, we show the relative difference in percentage of the neutron exposure with respect to the neutron exposure from the parametric calculations (τ_p) overlapped in both plots.