People's height can change from day to day, and even from hour to hour. When I graduated HS I was 5' 10" on a good day, in the morning. But more often I was 5' 9" to 5' 9 1/2". Then at age 40 I stopped doing springboard diving. At my next check-up, I was 5' 11" and have been that height at every doctor visit since. I guess hitting the bottom of the pool hands-first all those times was compressing the discs in my spine. My inseam is still the same, though; so I know I didn't just grow an inch at age 40!
Why do men feel they need to lie about their height? One of the first questions I ask someone when I'm fitting them for a new bike is their height just to get a rough idea of where to start. Most men add at least a couple of inches. The best one was just the other day, I asked and he replied 5'10.5". I'm 5'8" and may be even slightly taller than him. Probably had a 30" inseam. I put him on a bike that he could hardly raise his leg over. When his privates were being squished by the top tube I think he may have gotten the idea. It's quite funny actually.
Why would you not just start with an inseam measurement and cut thru any potential for crap from the start? Height isn't an accurate way of estimating the standover requirement, anyway!
Comfort is difficult to determine when no local bike shop has a Trek 7300 in both a 17.5" and 20". I was able to demo a 17.5, but not a 20", so I don't know which would be more comfortable. I thought there might be a technical way to determine the best size for a person.