By resolving one question, (potentially) we have discovered another! I do not know the answer to your Post Edit question. I would like to think it is a no, because I can edit my posts for a while, if that penalized us, I'd think it would of been brought to our attention sooner. I've never tracked how long, or thought even at which point does that option go away?
Maybe once a payout has occurred on the blockchain Story Edits are no longer possible because it's been verified on the chain? I edit posts, as well, I'm sort of a grammar fiend. It's never affected a payout to me that I've noticed. Curation Award or other wise.
Again, I could be completely misunderstanding this whole Reward Weight system too. I'm just now learning it, literally. I discovered it researching your problem trying to help resolve it.What I think has done this to you is the amount of posts you've made through the Submit a Story option. as explained by @rogue91
I have to say I think I'm inclined to believe edits count, because when you edit and you check out how it looks on your steemd.com profile, it said you've "authored" a post, not "edited" one.
I didn't make that many other posts in the past day that I would believe would cause an 85% drop in payout, but I edited WAY more than 4 times.
As a matter of fact, I'm almost positive editing is what did it because every time you edit a post, it bumps it to the top of the Active pages, thereby making it more visible and thus susceptible to spamming unless a limit is put on it.