Oxygen nonstoichiometry (d) of perovskite-type Ba0.5Sr0.5Co0.8Fe0.2O3-d (BSCF) was recently studied by combination of TGA, coulometric titration and neutron diffraction (ND). Analysis of the results revealed that the standard Rietveld refinement of ND data yielded strongly overestimated d values compared to other methods. Uncertainty of oxygen content from ND data was attributed to a strong diffuse scattering (ignored in Bragg diffraction refinement) leading to underestimated oxygen occupancy. A possible way to overcome the limitation of diffraction method is to use the total scattering approach, which is sensitive to local structure and accounts for the diffuse component. In the proposed experiment, we would like to collect ND patterns for BSCF, above the transition to paramagnetic phase, up to high momentum transfer sufficient to extract the accurate pair distribution function (PDF).