Yes, I often do nothing adjust the PH. If I measure it and it is somewhat close 3.3-3.8, I generally let it go as is. I go with minimal intervention as well, adding sulphites doesn't count, since they are naturally produced by the yeast as a byproduct. Oak to reds, since it just tastes better with oak in it. Acid to taste, sometimes after fermentation. I have twice added chemicals to get the PH closer to my desired range, I had some whites at 2.8 and a red one time at 3.3 and just felt they needed some help. I doubt your TA's are as close as you think they are, it is far to subjective. I took several college level chem classes and color work pretty good in the white wines, but not at all in the red, even when I tried to dilute them. PH is the way to go for endpoint.