Well I'm not sure if it makes any difference when upvoting comments, but I have a slider where I can choose how big impact each vote should take. I use 42% as a baseline for all posts I upvote, and only raise it if I really feel like it.
Steem newbies always vote 100 %, because their SP is lower it doesn't make much of an impact anyway, but when your SP gets higher, the system gives the chance to optimize it a bit, hence the slider. I'm not sure about the exact SP that's needed for it to activate though. I've powered up my SP every chance I got so I'm now possibly somewhere between minnows and small dolphins taking account my current SP.
Thanks a lot for the explanation, @gamer00. I didn't know that and I don't have such a slider (yet). But I'm looking forward to it now. :-)