Option 4 adds statistical distribution to the Nor140 functionality. There are eight percentiles shown, out of which one is user selectable. The class width is 0.2 dB over the entire 130 dB range.

The statistical distribution calculations employs the F time constant and applies to the spectral weighting networks (A and C or Z) as well as all the individual 1/1 and 1/3-octave filter bands (if applicable).

The back-erase feature, which deletes up to the ten most recent seconds of acquired global data prior to a pause upon resuming, updates the statistics buffers as well to maintain consistency.