I knew this at one time and can't remember because I don't show.
I THINK more weight is allowed in the shoe for flat-shod classes. Or they may possibly be allowed to use a very light package on them.
Whereas lite shod may be just the standard keg shoe that one can trail ride with.
This PWHAT show bill indicates lite shod can show Western and English.
Flat shod classes were Model and also Park Pleasure. The comments for Park Pleasure state that bands can be used, so the horse is limited in the classes it can show in. The bands make me think that light packages may be allowed. Welcome to Pwhat- Our Show Schedule
You could always e-mail PWHAT and ask them; I'm curious myself now that it's been brought up - lol lol