So since late 2011/early 2012, my community has went from IPBoard, to XenForo and to this date, back to IPBoard.
I am finding that not all of my posts are being converted, but the only ones that are, are the ones which were originally there from my previous IPB to XF conversion. The posts which were made while the forum software was XF, are not there.
This is what my conversion page currently looks like in a screenshot:
(Note the source rows of the posts)
Do note that this is the correct database, and that I'm using xf_ as my prefix for converting. All member accounts have been moved over successfully however.