[Steve_Ray]

Indeed, if you want the equivalent of "Space Above/Below" in a vertical
direction (in rotated text), you need to use paragraph indents.

I'm not sure I follow, but I'll do some experimenting with 'indents.' That
still wouldn't appear to explain the variation from one cell to another --
i.e., why text is correctly horizontally centered in some cells but in others
is hugging the 'top' border line of the cell (which, in the case of
'vertical' text, is actually the 'left' border line).

Again, these cells are all formatted identically; there are no alignment or
positioning variations, at least none that I'm aware of.