There are 67 records in the Excel worksheet (67 different names and addresses). After completing the merge, only the first 30 records appear in the resulting document. Since there are 30 labels per page, that would seem to indicate one more full page and a partial page somewhere - but I sure can't find it.

Dunno about cell alignment, seems to me that if it was actually simple, then the obvious approach would work: Table Properties > Cell > Vertical Alignment > Center. But for some reason that doesn't work.