Darryl,
As Dan mentions, if you used a really short focal-length lens and placed your image at the edge of the image circle, you could easily be 1.5-2 stops underexposed. That said, even with extreme shift and rise, a good part of the image should be from the center of the image circle and exposed correctly. You'd be more likely to notice the underexposure as fall-off toward one corner of the image.
Using tilts and swings on the back does end up with a configuration that has different bellows lengths for different parts of the film. This can affect exposure slightly; the areas farther from the lens getting a bit less exposure. I've never experienced a significant exposure problem with extreme back movements and black-and-white negative film, but it might be an issue with transparency material.
If you're interested in keeping near and far in sharp focus, then read the article on the LF home page about choosing the optimum f-stop here:
https://www.largeformatphotography.info/fstop.html . It's a much more reliable way to ensure focus where you want it and optimize diffraction degradation at the same time. Hyperfocal distance and LF don't go together very well IMHO unless you're just using your camera point-and-shoot. Judicious use of movements often allows us to get everything sharp that we want and use a more optimum f-stop.
To answer your question though: If you've got your camera set at a specific hyperfocal distance, and have tested your depth-of-field/acceptable focus for a specific distance range, then, no, you don't have to focus if you're certain the elements you want sharp are in that particular distance range. Once you introduce any swings or tilts (or even rise/shift with some lenses/cameras), all bets are off and you'd better pull out the trusty loupe
Best,
Doremus
