The Expanded Bible: New Testament is indeed based on the New Century Version (I'd have known that yesterday if I'd read the introduction). The introduction says it is a "modified version" of the NCV. Since William Chamberlin and I both need to catalog this new work properly, I looked for differences. I found several with the briefest of searches. I did not consider the bracketed expansions. One such example is found in Matthew 5:3 (I've removed the expansions here):
NCV Those people who know they have great spiritual needs are happy
EB-NT They are blessed who realize their spiritual poverty
I'm not trying to establish any theories or complaints - just to properly categorized the base text.