It looks like they are going for what they have solid proof of rather than over charging and possibly loosing.
http://www.military.com/daily-news/... selects rarely used charge for Bergdahl caseUS military selects rarely used charge for Bergdahl case
http://www.military.com/daily-news/... selects rarely used charge for Bergdahl caseUS military selects rarely used charge for Bergdahl case