Secesh, your table seems to assume an average male height of 1920mm for the O and S scales, which is almost six and a half feet - pretty tall
1750mm tends to give better results, which would make:
O Scale = 36mm = 1/48
S Scale = 27mm = 1/64
HO Scale = 20mm = 1/87
A "true" 28mm figure in wargaming scale (foot to eye) would come to about 31mm in railroad scale (foot to top of head), and if you add a few mm of equipment and the base, you're closer to O than to S scale, although neither is perfect. For "Heroic" 28mm (which tends to be around 33mm railroad scale) O scale is pretty much spot on.
Dsfrankevo has some pictures around of BF:ECO ("true" 28mm") and Devil Dog Designs ("heroic" 28mm) miniatures with O scale buildings, which I think shows that scale works very well:
http://www.mongoosepublishing.com/phpBB2/viewtopic.php?t=25432
http://www.mongoosepublishing.com/phpBB2/viewtopic.php?t=25430
http://www.mongoosepublishing.com/phpBB2/viewtopic.php?t=25005
In my experience, if you can't get it spot on, you're better off scaling buildings and vehicles a little too big or they'll look like toys.