The 64-bit DPE is for computational purposes, and has had known issues in the past as being the culprit behind certain processes going south (why that stuck out when you said you are using it).
As far as an audio file itself is concerned, a 64-bit
audio file is overkill to the max... it has already gone far beyond the capability of human hearing at 32-bit. The computations associated with 24-bit files is why higher word lengths are used (to allow for higher precision math)... the end result is still dithered back down.
Unfortunately, as technology advances, everyone thinks "more is better" when the ultimate glass ceiling is the ears of the listener... Technology surpassed human hearing capabilities long ago, so many can only "hear" this difference when they are using visual tools as a crutch.
The digital clipping is sort of a "hard stop" issue to always keep in mind. Even though processing can be done to compensate/tolerate this, certain media forms, algorithms, and the like most certaintly cannot (and it is those that cannot that will bite you).