Meanwhile, in the bottom right corner, you'll only get the correct planet type if you set the center of the slider to precisely the middle of the signal. Most of the time, this doesn't make a difference, but if you look up @Frillop Freyraum 's earlier picture here, you'll notice that it's just slightly off the middle of the signal and giving a wrong type already.
You might have missed it, but I already pointed this out...
Look closely (zoom in if you like) and you can see your tuner is ever so slightly to the right of the circle centre. Did you move it 1 pixel to the left to see if it changed to RIW?
All I've seen so far is evidence that the FSS provides very precise changeover points (frequencies) demarcating the boundaries of the body types.
I've still seen no evidence that the FSS itself allows overlap. The only uncertainty appears to be human interpretation of the FSS output.