Regarding the headings...
This is a little embarrassing!
To be processed in this way, the heading must have an initial capital.
I just didn't think to bother with this for testing.

I would still like help regarding the date conversion.
I have vague recollections that there is an option somewhere, possibly to do with styles, to set whether or not dates are converted, but I can't find it now.

I also continue to be very intrigued by the format tracking option.
As I vaguely understand it,
either
you make some small formatting change, and the system assigns a standard style to it.
or
the system looks back at the styles you have used, and assigns the closest one.
I would really appreciate some illucidation on this.