If you have a form with a repeating table and then you populate it with data, then save the form, the saved form (the xml file) will have the data. If you reopen the original form (the xsn) it will not contain the data and you must repopulate it.
You can also auto populate the repeating table(s) when opening the original xsn form. You can do this using code, I did this in JScript an loaded my repeating tables from an XML file.
Hope this helps