My Trek 1.1 has a stem I'm not familiar with, and my new manual won't be here for a few more days.
It's a Bontrager sport stem, and it looks like it clamps to a large tube with 3 spacers below it, and a cap on top with a hex screw. It looks like I should take the cap off, loosen the clamps, then re-arrange the spacers to adjust height. If I do that, am I left with a big stub sticking up? Does the screw on the cap allow the stem tube to move up and down?

And finally, why did they do it this way? It looks a lot heavier than a regular type stem.