Try it or check the screenshot and you'll see that "hB" heading is a level 1 heading and in the XDOM used to render the view it's not inside "hAB"...

You are relaying too much on the resulting HTML, which is not what is manipulated here.

The include macro is part of the hAB section and nothing it produces can change that from XDOM point of view because what you end up with is the hAB having as content a macro marker with the result of the include macro execution.