The chart shows the same thing as the w6000 manual's chart, some of the same descriptive confusion exists in the w6000 manual as well.
So I am going to assume the chart is what is right, so the max above/below the screen you can mount the projector is about 6.3 inches above or below (16cm according to the chart) for a 100" 16:9 diagonal, and anywhere in between those two points, with the center of the screen being the zero offset start.
I believe the same descriptive mistake exists in the Benq w6000 manual, so the entire range is 12.5% of the 16:9 diagonal (6.25% up or 6.25% down of diagonal), or 25% of the screen height (12.5% above or 12.5% down of screen height). You could also say 125% of screen height, since you are referring to the entire range, but it's essentially the same thing as long as you note that the Zero Offset position is set to center-point of screen. This reminds me that I need to fix my own descriptive confusion in my calculator of the offsets (for next version anyhow).
This would also concur with some of the reviews I have read on the Benq w6000's lens shift. Art @ pjreviews.com also noted he could pretty much put the projector anywhere between the screen, but not too far above or below it (which seems to concur that you can mount at center-point but overall only get a few inches of the lens being above or below the screen). Not as good for a ceiling mounting position (high ceilings will need longer drop poles), but great for shelf mounters.
I believe the reason for the confusion and mistakes in the manual are as follows:
It's mainly because when we are dealing with center-based offsets, if you say 12.5% above the screen, they often mean 6.25% either way because they are starting from the center, and the center is only half the overall screen height distance. To make things more confusing, they sometimes go back and forth talking about % of screen height or % of diagonal. It would be much easier if they would stick to one formula throughout the same manual.
It's really quite a simple concept, but somehow these manuals always manage to make it confusing. Never ceases to amaze me how a simple concept can be made so confusing.
Also, I read on one site (not sure which) a while back that the reason these DLP's don't have much lens shift has to do with the way some of the assembly is in the way and restricting them in the design. The Benq w6000/w7000 seem to be the rare exceptions here (and having a center-based offset helps more), although I'm not sure how much lens shift some of the super expensive DLP's have.