Yeah those Probikekit sizes are nonsense. Euro sizes have stayed constant while American sizes have suffered from bracket creep but not by THAT much. In general my advise is that if you have an expanding girth you should actualy ignore it for cycling clothes in most circumstances and go for the size you would be if you weren't carrying a "spare tire".

Lycra is stretchy and will easily accomidate some stretch and its more important to get the fit right in other area's. A tight fit is a good fit with cycling clothes. I wear a small (2) in Nalini to get the length right as I'm 5' 1" but I have a 31" waist on a good day. No problems and they fit fine if a little tight around the waist but that's good. I do have some mediums (3) as well but they are TOO long in the torso and it bunches up at the bottom which isn't a good look. I also have a large (4) winter top from last year when I was a bit heavier but it realy is WAY too big now.

Regards, Anthony