What on God's green earth are you talking about?
A horse that stands 14.2 hands or under is a pony. Period. End of story.
That is just the way it is. xD
Height actually has nothing to do with it. Ponies have different PROPORTIONS to a horse. Their legs are shorter when compared to their body, and their heads are thicker. Some horse breeds have shorter members - Quarter Horses are still horses even if they are 13hh, a Quarter Pony is a mix of QH and pony, not a short QH.
Height rules were only bought in for showing. It is not a reliable thing to base your information on. For example, here in Australia, buckskins and duns are shown in the same class - all duns that is, not just bay dun. Yet palominos are in their own class. If one went by the "show" rules, then you could argue that buckskin and dun are the same thing, when we all KNOW they are not.
Mods, grant me the serenity to see the opinions I cannot change, courage to change the ones that should change, and the wisdom to spot the trolls.