Okay, I re-read that particular sentence and I agree that Chang meant Sq/CC EA jobs and not Sq/CC jobs.
Since these jobs are open to O-4s, you are essentially sending the message that you better get your Masters knocked out early to be competitive for one of these "opportunities." And this takes us right back to the pre-Gen Welsh days. It makes sense for an IPZ O-5 applicant to complete the AAD beforehand but not for an O-4 applicant.
And if you are a Major who gets selected to be a GO Exec, you are more than likely to get a school slot later and a Master's along with it. So this is really not an issue, unless you just wanted to see how devoted someone is to climbing the career ladder.