Why does Word create multiple revisions when auto-hyphenating?

[Eric]

In Word 2003, I've added shading to a paragraph consisting of multiple lines.
Word seems to have broken this into multiple separate revisions, based on the
revision bubbles in the right margin.

There is a lot of auto-hyphenation in this paragraph, and what seems to be
happening is that Word avoids including an automatic hyphen break in a single
revision. In other words, if a revision spans an auto-hyphen, Word finishes
the revision at the hyphen and creates a new one after the hyphen.

Am I correct that this is the way Word works? If so, why? I can't figure out
the rationale why Word would work this way.

Thanks.