In XRD Rietveld refinement for two phases using Fullprof software, I got the same phase fractions i.e, 71% of 1st phase and 29% of 2nd phase for different substituted data files i.e, for 5%, 10%,....substituted data files. I entered correct occupancy fraction according to the space group. But, I got the same phase fractions. Please do help in solving this problem.