In the high-performance and low-cost (Mn,Fe)2(P,Si) magnetocaloric compounds, the detrimental hysteresis has been significantly reduced by balancing Mn:Fe and P:Si ratios, which consequently leads to loss of site-ordering of Mn and Fe atoms in alternate crystallographic layers. We propose on using neutron powder diffraction to resolve the distribution of Mn and Fe, which can not be resolved by X-ray diffraction. Furthermore the strong and weak magnetism in alternate atomic layers and their interplay, suggested by first-principle electronic-structure calculations, can be explored by neutron diffraction through the order and disorder states induced either by temperature or magnetic field.