Yes I have noticed my numbers going down (payout still rising) and people commenting without first upvoting the post.
The changes I made was that I always used to 100% upvote those that upvoted my post and commented. Now I am down to only 10% and still only to those that upvote prior to comment. I do occasionally still upvote 100% but you need to be careful you do not deplete your own account.
that is exactly the same strategy of mine, I go with 100% sometimes, but generally I use 10% of my power, but I never ignore the author's right who made effort to create a valuable content, unfortunately some people do