Automatic change of TODO

[Alessandro Pacaccio <alessandro.pacaccio@gmail.com>]

Hi!

I've an outline like this:

* Project A
** TODO Task A-1 [0/3]
*** TODO Subtask A-1-a
*** TODO Subtask A-1-b
*** TODO Subtask A-1-c

where level 1 heading is the name of a project, level 2 heading is a generic
task broken into three level 3 headings.
As suggested in section 5.5 of the manual, I've hooked the org-summary-todo
function to org-after-todo-statistics-hook, in order to automatically change the
level 2 TODO to DONE when all the subtasks are DONE.
Unfortunately, when I change to DONE the first subtask, an unexpected TODO is
added to level 1 heading:

* TODO Project A
** TODO Task A-1 [1/3]
*** DONE Subtask A-1-a
*** TODO Subtask A-1-b
*** TODO Subtask A-1-c

From now on, the switch TODO->DONE or DONE/TODO applies to level 1 heading, even
if the [/] cookie in level 2 is correctly updated:

* DONE Project A
** TODO Task A-1 [3/3]
*** DONE Subtask A-1-a
*** DONE Subtask A-1-b
*** DONE Subtask A-1-c

Is there a way to apply the automatic change of TODO to the parent heading only,
as below?

* Project A
** DONE Task A-1 [3/3]
*** DONE Subtask A-1-a
*** DONE Subtask A-1-b
*** DONE Subtask A-1-c

Thank you.
- Alessandro