Problem with point in state change hook function

Problem with point in state change hook function

[zyg]

My brain works in two non-standard org ways:
- I don't like having the =CLOSED= timestamp outside of property drawers, and
- no =todo= tag (or a =todo= tag of "" if you like) is still a =todo= tag
  and often means =DONE=.

So standard state change logging doesn't work for me.  All I really
want to track, though, is the timestamp of the latest state change. Hence:

#+begin_src emacs-lisp
  (defun my/log-state-change ()
    "logs timestamps in PROPERTIES for any todo-tag state change (LAST).
  "
    (interactive)
    (save-excursion
      (let* ((stamp (org-string-timestamp nil t t nil nil nil)))
        (org-set-property "LAST" (concatenate 'string org-state " " stamp)))))
#+end_src


#+begin_src emacs-lisp
  (add-hook 'org-after-todo-state-change-hook 'my/log-state-change)
#+end_src

This works fine except for the following conditions:
- the =todo= tag is changing to a non-nil value,
- there is not (yet) any heading,
- point is exactly at the start of the header (after stars and =todo=
  tag if any), and
- there is no properties drawer yet.

In this case, point moves from the header to after the properties drawer.

A few examples showing intention and bug (representing point by ^):

Example 1: works
- before shift-right
 #+begin_example
 * ^test
 #+end_example

- after shift-right
 #+begin_example
 * TODO ^test
    :PROPERTIES:
    :OPEN: [2012-08-22 Wed 15:51]
    :LAST: TODO [2012-08-22 Wed 15:51]
    :END:
 #+end_example

Example 2: buggy - point shifts
- before shift-right
 #+begin_example
 * ^
 #+end_example

- after shift-right
 #+begin_example
 * TODO
    :PROPERTIES:
    :LAST: TODO [2012-08-22 Wed 15:51]
    :END:^
 #+end_example

Example 3: ok
- before shift-right
 #+begin_example
 ^*
 #+end_example

- after shift-right
 #+begin_example
 * TODO ^
    :PROPERTIES:
    :LAST: TODO [2012-08-22 Wed 15:51]
    :END:
 #+end_example


Example 4: strangely, this works (standard TODO -> DONE -> "" cycle)

- before shift-right
 #+begin_example
 * DONE ^
 #+end_example

- after shift-right
 #+begin_example
 * ^
    :PROPERTIES:
    :LAST: [2012-08-22 Wed 15:51]
    :END:
 #+end_example


Any ideas? How can point change if you have a save-excursion in place?
My main thought was that the properties drawer is being inserted before
point but /only when/ there is no heading. I've spent some time
squinting at org-entry-put to check this, but debugging let alone
understanding org-with-point-at is way beyond me.