Correct, it's NOT balanced... nor CAN it be, as yyz67's graph illustrates.
I suspect most of us have been dealing with this issue for quite a while, and are aware of the difficulty of finding a "happy medium" where a quite compressed lead tone and a much more dynamic clean tone can still be feel "somewhat" in balance, in actual performance. But– at least speaking for myself– thoroughly understanding the issue isn't always enough to make the frustration completely go away... especially on quick plug 'n play/no soundcheck situations.
So much has to do with setting the levels of the patches, based on specific touch/dynamics of your playing (at least, for me). When I use the precise physical touch dynamics that I used when setting up the different patches, it's great. When, for one reason or another, I'm hitting harder, cutting thru a louder mix, or whatever... then the "balance" that was so correct for the last gig is now disturbingly wrong.
And THAT is where it can be helpful to have a post-amp volume pedal... to allow some form of compensation, in real time.