Interesting, but in this case it wasn't that it was ranked lower, but that one day I had 25 domains indexed fine and the next day they were no where to be found

Interesting, but in this case it wasn't that it was ranked lower, but that one day I had 25 domains indexed fine and the next day they were no where to be found, i.e. not in the index at all. And I had plenty of other domains (not in that adsense account) that were still ranked fine.