emacs - Org-mode: timestamp + effort -> time range -

i liked question , answer @ emacs - org-mode: creation time range effort estimate - stack overflow. regarding taking scheduled item , effort estimate , producing time range.

i wanted different result, can't see how modify (i imagine modifying org-deadline easy). instead of scheduled item, wanted act on timestamp.

in other words, (cutting, pasting , removing scheduled: linked question),

* todo sample todo   <2014-04-18 fr 10:00>   :properties:   :effort:   1h   :end:

would become

* todo sample todo  <2014-04-18 fr 10:00-11:00>  :properties:  :effort:   1h  :end:

i considered org-time-stamp , org-add-planning-info, no success.

assistance appreciated.

GHI