I'm baffled by the behavior of styles. (Word 2003)
I've defined about a dozen styles using the New Style button on the Task
Pane -
some character and some paragraph styles.

When trying to apply the styles to some existing documents, by highlighting
the word and clicking on the new style, often the result is not at all what I
expected. The font size is different, bold and underline are sometimes
included when they are not included in the style. If I mouse-over the style
in the Task Pane "Pick formatting to apply" list, the description is right,
but the resultant text is wrong.
then clicking Modify to Match Selection in the Task Pane list, but there is
no change in the result next time the style is applied.

I must be missing some important concept about applying styles. Can anyone
point me in the right direction please? Thanks!
I've tried using the formatting buttons to correct the problem, then