1935A Hawaii $1 SC Block - Did I miss something

[Coin Armour]

The following note sold for $200 above other asking prices of the same grade and same block. I am not sure what I am missing here...any info would be appreciated:

 

http://www.ebay.com/itm/HGR-1935A-1-Hawaii-S-C-Block-PMG-GEM-UNC-66EPQ-/200976667288?_trksid=p2047675.l2557&ssPageName=STRK%3AMEWAX%3AIT&nma=true&si=DBcGWj1LFn%252BXyu72M%252BDVnlzBTjY%253D&orig_cvip=true&rt=nc

[EastCoastCurrency]

Odds are that two people had nuclear snipes and it just went way too high. That seller also has a very close following of bidders. I would normally suggest that someone thought it might have upgrade potential, but at that price and with those back margins I am not sure that would be make any sense.