So if some of your upvotes come from what the software thinks is a voting ring, and/or if a few people flag your posts, they will drop to #80 or below very quickly.
Several technical solutions have been suggested in the past, but personally, I think it's a mistake for flags to count so heavily in the ranking. I think flags should not affect the ranking, but that sufficient flags compared with upvotes should result in deletion.
Consider. At the moment if a few people take exception to your posts then they will disappear from the front page and get very few views. Vigilant vigilantes can bury items quickly. Worse, spam gets buried, but not deleted.
If an item truly is spam, let it remain visible so that more people will flag it and thus cause its deletion. Simply burying it runs the risk it will never get deleted.