If all measurements are in unsmoothed form, and on the All SPL tab click Actions, smooth to 1/48, the graphs are smoothed to 1/48, but the 1/48 numbers do not appear in the legend. If you smooth to 1/24, the smoothing will work correctly and the numbers 1/24 will appear in the legend. If you then smooth it down to 1/48, the smoothing will occur correctly and the numbers 1/48 will be visible in the legend.