15/8

Hello group. Harmonic entropy site's kind 'a deserted, so I thought
I would post here...Does anyone know why the the main harmonic
entropy graph does not include 15/8? I noticed, in another ranking
of interval dissonance (Campbell and Greated, 1987, ie, 2/1, 3/2,
4/3, 5/4, 5/3,6/5,8/5,9/8,16/15), that this wonderful interval is
also excluded. (15/8 is a personal favorite of mine; leading tone
and tonic combined in one chord!..., and, to my ear, and in my choice
of chord construction, it serves as a 'near-octave....)

thanks, Kelly