As already mentioned, the amount of lens shift provided is minimal, but that said, if it's got enough for your setup, that's all you can ask for. BenQ again provides a chart, but they mention that it may not be accurate. It seems not to be.
The W1500's lens shift range allows for the following. If you are ceiling mounting the center of the lens can be placed anywhere from being almost 6 inches above the top of the screen surface to about even with the top.
If table mounted, then it would be almost 6 inches below the bottom of the screen, up to even with the bottom of the surface. That's based on some quick measurements. BenQ's chart indicates only about 2 and 2/3 inches range, whereas we came up with a little over 5 inches.
The lens shift control is hidden behind a small spring loaded door, just behind the lens controls
I'd definitely recommend doing your own lens shift measurements before you mount the projector.
BTW with this little lens shift, you can't mount the projector up high on a rear shelf, although, that wasn't likely anyway, since the zoom lens isn't telephoto enough to get to a rear wall in many rooms, unless you have a really super-sized screen for the room's size.
Bottom line: While there is some lens shift, and it should definitely allow an installation to be fine tuned easily, remember that it's a few inches of vertical range. By comparison, LCD projectors with lens shift like the two Panasonic projectors or the Epson 8350, 4030, and 5030UB, can be placed anywhere from over two feet below to over two feet above, the bottom, and top of your screen.