I think the automaticaNumbering is not perfect, I found a way to use AutomaticaNumbering.
That is :Create Your Own Stylesheet. You can search StyleData in Help,
And the SectionNumbered gives good example when see the CellExpression, and we can modifiy it in our personal-stylesheet.nb
If you want to remove AutomaticaNumbering of some stylesheet, just CtrL+Shift+E and remove the part related.
Shortcut to insert CounterBoxShortcut to insert CounterBox
and I saw this which maybe also helpful
The picture show the case: find a buil-in cell-style is really AutomaticaNumbering, but with no CountBox, it's in the parent stylesheet.