Give it a shot.
Just create  a NEW XLS file.
Create a Workbook_Open subroutine
and have it display the fullname (activeworkbook.fullname)
then save it as a template and exit.

Now, double-click on the template.
What happens is that you open a COPY of the template, not the actual template.
even though the activeworkbook.NAME is the same as the template (including the
.xlt)

I think it's a function of the intended use of templates.
By definition, a TEMPLATE is supposed to provide the FRAMEWORK for a new file.
Therefore, The Exalted Ones at Mt. Olympus (er... Microsoft) decreed that
you're not really "opening" the template file, but opening a "copy" of the
template file.
But the copy doesn't seem to retain a record of where it came from.

If you can find a way around this, we shall sing your praises...
er.. maybe not.. you don't want to hear me sing.. that's why I'm a programmer!