A quick update: I returned the sweater today. Have my parents visiting so forgot to take a picture. The sweater was just too big all over, not just the length in the sleeves (which was ridiculously long) but also the width at the neckline and in the waist (I wanted something loose in the waist but this one was just too much). I didn't think the XS would be all that much better.
I also didn't like the reverse side look (white with navy stripes) as much as the navy with white stripes. A big reason I considered this sweater was the reversibility, and even if it had fit, I wouldn't have liked the other side.
That said, it is a gorgeous sweater and the cashmere is to die for.
When mom and I returned it today they had the same sweater in the white/grey in the store. Did not try it on but tried on some other sweaters, none of them worked for me (gorgeous but didn't fit).
Did pick up a couple of sweaters in petite size and on sale from BR. At BR there was a similar reversible cashmere sweater, similar weight, charcoal/white plaid there in regular sizing and it fit great (hit at hip length on me, not overly boxy) and I nearly bought it... except it had a mock neck and I just don't like sweaters around my neck. Super cute though if anyone is shopping and looking for a heavy weight reversible cashmere sweater.