I have some info on Honda surface roughness that refers to JIS B 0601.
The S symblos are for finishing using inverted triangle symbols. 100S Max. = 0.1mm, which is one triangle, and 2 triangles =25S Max. which is 1/4 of one triangle.Three triangles =6.3S Max.which is 1/4 of 2 triangles
These are supposed to correlelate to the R max. or Ry.
Sorry I can't give you a better answer, but had this class about 3 years ago, and just have a copy of the hand out.Suggest you refer to JIS B 0601