Thank you very much @stevestrange for your comment and showing your graph. I think there is nothing wrong with self-upvoting too, it all depends on how you want to allocate your voting power, yourself or others. Whatever you do there will be people to disagree. If you self-upvote they will say you are selfish and rape the pool when you have invested thousands in SP, and if you only upvote others, there will be people saying that you are buying followers and votes back.
I have upvoted this comment 100%.