I would definitly buy into the idea that manufacturer's rig their recievers so that most of the volume gain is in the first 50% of the volume control. However, I can definite noticable difference between then say 22 and 25 on my reciever. Is it a big a difference as 12 and 15...probably not. I guess my biggest concern was whether or not I could accidently damage my speakers with my current 100W reciever besides clipping.
I guess what really brought this on was a DVD I was listening to a few nights ago. I was listening to Rodger Waters Live in the Flesh and on a certain part of "Another Brick in the Wall(II)" I could hear a couple crackles coming from my left speaker. It only occured in one part of the song and when I went back and replayed it, it crackled in the same spot. More then likely it's the DVD. I then popped in a CD that has considerably more bass and listened at a comparable volume and it was smooth as silk.
Anyway, this just started making me paranoid that I might be damaging my speakers but more then likely is a crackle on the DVD and I have nothing to worry about.