Since 2004 the Cashmeres on ebay was selling for between $835 and as high as $2150 which was a tad ott IMHO, on average the record was selling for around $1500, give or take a bit half what Tim valued it at in his guide, which is after all a guide. That btw is for copies that popsike have picked up on, know there has been more than the copies stated.
50 copies only, I bet there's been almost that up for sale via auctions, lists and sales boxes at venues the past few years, have seen it for sale often enough was also told one seller on e-bay had multiple copies, rumour or fact dunno?
as for the understating of values by those who should know better, give us some examples? the so called understatement could after all be just a honest opinion, maybe the last value the one who should know better saw a record sold for?