I am not sure that I understand the problem.
In my truck, stock factory audio, centering the audio balance does not sound "right".
Speakers differ so some audio adjustment is necessary - that is the purpose of balancing speakers. Not that the indicator is necessarily dead center.
So I change the speaker's balance until the sound is "centered" on me as I hear the audio. And that may change with a passenger or a window cracked open. Or stuff piled on the passenger side/seat. Or even the DVD being played....
So tune/change the balance(s) to what sounds best to you and remember the resulting settings in case a reset is needed.
And I do much the same with home audio. Always need to tweak the balancing after furniture moves or sitting in another listening spot.