You should see the same results as the other Subreport on the Report Header.
The option 'Keep Object Together' ensures that the object does not force a page break when there isn't enough space (to fit the data in that object) left on the remainder of the page.
There is also a 'Keep Together' option for the sections, however from my experience, the 'Keep Object Together' option over-rides the 'Keep Together' option on the sections.
-Abhilash