I wouldn’t worry much about the normalization as long as you have strong levels, especially since you are re-sampling, you are just moving 1 and 0s around inside DT. In reality, you are getting out what you put in, with perhaps a small change in gain, that’s it.
But, perhaps you have super-human hearing. There does seem to be a lot of people in the forums with super-human hearing. So, if you think you can hear the imperceptible, you will hear it.