Word autocreates styles no matter what

[Nancy Allison]

I've found a solution to my problem, but I don't understand the problem and wonder if I'm missing something.

You know how Word creates new styles if you use the formatting toolbar items within a style. So, if you select a word and click B in the toolbar to bold it, in your Para style, Word creates

Para Bold

and sticks it in the Styles and Formatting pane.

According to Word help and every online site I found, if you deselect "Define styles based on your formatting", (Tools/Autoformat As You Type tab), this behavior goes away.

It doesn't. Selected, deselected, Word keeps adding new styles. Why? Am I missing something?

In case you're wondering, the solution -- regardless of whether that option is selected -- is to create character styles and format exclusively with them. 

Have you encountered this situation?