[JKT]

If you think about it, it makes some sense - the sub-section heading is giving you the total of any sub-sub sections. If you could input a figure into that sub-section heading, then it would no longer be the total of the sub-sub-sections.

However, how you get around this I don't know. It seems that you need to have your outline set-up as is before you can use it in this way...