Comparing the outcome of two matching procedures relating simulated halos (plain black histogram) to detected sources (photon-based matching is a dashed blue line, and position-based matching is a thin orange line). A simulated halo is flagged as selected (I_main = 1) whenever it is (solidly) matched to an extended source in the detection catalogue. The details of the matching algorithms impact the flux distribution of detected sources, especially at flux below a few 10⁻¹⁴ erg s⁻¹ cm⁻², with deviations up to a factor 2 in certain bins.