I would think that's true. If my intel gathering is correct, lowering preboil is supposed to effect protein coagulation (clarity), round out hop bitterness, and assist the yeast in getting the ph down to where they need it. So if you dont have a clarity issue, your hop bitterness is fine as-is, and you are using a more robust yeast (like 1056?) then I'm guessing preboil acid isn't really doing much for you.
Kai says ph has a part to play in isomerization, utilization and the quality of perceived bitterness. I dont know if that's been explored. In a more robust beer I wouldn't worry about it. I just tried it in a Helles-ish beer.
Kai says the reason yeast release hydrogen ions and drops ph is so they can easily uptake nutrients and expell co2 and alc. I imagine helping them get a leg up on that may be more important with some finicky lager yeasts.