Hello,
This requirement (adding at least one content between tables) is needed to follow OOXML specifications, otherwise a corruption message may appear (maybe some specific revisions of MS Word doesn't display it). It we generate two tables without adding at least a paragraph appears an error using MS Word 2007, MS Word 2010, MS Word 2013... and other DOCX readers. When you move a table after other table, the tables are merged into a single table in almost all cases.
Please use the recommended approach.
Regards.