This still doesn't make sense because why would only homes on the low-end appreciate? If anything homes on the high-end should be appreciating faster because the people who live in them can afford to do more improvements.
Btw those disproportional numbers can be easily real anywhere in the world even in much bigger ratios, I can confirm them from Europe - if you want to invest in properties, location is absolute top priority as we all know that. Those properties appreciate faster than average market, don't suffer much drops in crises, and of course are at most desirable locations for whatever reason.