Hi,
I think you should take a look at our qRules tool: http://www.qdabra.com/en/products/qRules.aspx
Working with repeating tables in InfoPath can be complicated and many of the scenarios you mention are best done (or only can be done) using code. qRules allows you to use code without writing the code, you inject our code into your form and then use rules in InfoPath to execute the code (which means you don't need to know the code).
qRules has a bunch of commands associated with working with repeating tables, inserting, copying data between and deleting nodes.
Ted