I don't think Specialized is recommending you fit on a saddle narrower than your sit bones. You'll note, the top right of the scale indicates "and wider."

I honestly have never measured a woman who had sit bones wider than 160mm. Most have been in the 130-140mm range.

And yes, these are only guidelines. For example, Specialized would fit me on a 143mm saddle. I've been riding a 130mm saddle since 2004. I like it. When I tried the 143mm saddle I ended up with saddle sores.

The fit process doesn't end when someone leaves my office. I guarantee my fit so if someone isn't happy with their fit or satisfied with their saddle, I will see them again until I can make them happy. And in all the years I've been performing fit, I've only ever needed to see someone again twice.

BTW, I've only been demo-ing Specialized saddles for a year but I've been performing bike fit for the past six years.

Now Knotted, tell me more about pelvic rehab. I sit firmly on my soft tissue (not my sit bones) and have been since I started riding about 10 years ago. I've noticed no negative issues.......what should I be looking for?