SEDs built from Herschel and other wavelengths for sources lying towards the SiO peaks (except for those shown in Fig. 4). The curves are grey-body models fitted for data at wavelengths  ≥ 160  μm. The one-temperature grey-body fit (black curve) is consistent with two-temperature grey-body fits (green curve). Error bars correspond to 30% of the integrated fluxes. No model can reasonably fit source #27.