I think what is happening for my experience is that they are all light bats so as @sarg
said it may be more noticeable . With most of my bats I have an inch cut off the handle , which is a loss of .3-.5oz , so adding a counterbalance is putting some of that weight back onto the handle knob , thus returning the bat to something more closely resembling its original balance and feel .
I tried the counterbalance on all 14 of my bats . With my c.a bats (6 of them ) I dont cut the knob off because they are shorter bats to begin with . I found the counterbalance worked for the 4 lighter ones , not so much for the two heavier ones .
With my j.p.g i noticed a minor improvement .
With my s.f ( which is short blade , long handle , no knob cut off ) I felt it made the bat feel worse . But perhaps this bat has extra handle sticking out past my top hand anyway which is already fulfilling a similar job .
With all my other bats ( all g.n ) i noticed a significant improvement , regardless of weight .
Having said all this , all my bats are between 2lb6oz and 2lb9oz .
So I'm going to keep the counterbalance on 10 of my 14 bats , for the time being anyway .