There are couple of reasons for that.
- Since the post is targeted for new users most of the up-votes are also from newbies. Since the votes of newbies are generally not worth much the rewards are also generally lower.
- Many of the upvotes have been given post the rewards deadline.
Though it is sort of a bummer I don't mind because I think in the long term this will pay off. This also highlights the issue of undervalued posts that the community has found useful. I am working on scripts to identify these kind of posts so that we can retweet them and it can reach out to more users.