It's also possible that there are no "rankings", and the TOC doesn't represent how much ppl liked a chapter from 7 weeks ago. And it's actually just a reflection of popularity, promotion, and whats going on in the current issue's chapter.
I doubt the editor's would randomly decide to put a bottom dwelling series that isn't popular to give it a super push if the series didn't at least a moderate fanbase already. Some popular series have been at the bottom before. It's possible that maybe being at the bottom doesn't ALWAYS mean that a series, or a particular chapter, isn't doing well.