Bruce, you've got it. The minimum and maximum amounts tell you how far you can rack the standards apart, which in turn tell you what focal length lenses you can use. Note that telephotos are the exception to this; for example, my Fuji 400mm only requires 260mm of bellows draw.
When the bellows are fully extended or compressed movements can become difficult, if not impossible. So if you like wide angle lenses, the use of a very flexible bellows or a recessed lenboard may be required. On my Gandolfi I can compress my bellows enough to use a 75mm lens - no movements, however. With a bag-bellows (no pleats) I can have some movements. I can extend my bellows to 485mm, so I don't have to worry about problems with movements with my longer lenses, since a 305mm is my largest normal lens.
Hope that helps clear things up for you.