Unfortunately I am still not able to reproduce this issue.
This is what I've done:
1. Create a test project in 2013.1.911.
2. Add an Excel sheet as a data source.
3. Copy the project to another machine and open it with 2013.2.1327 in Visual Studio.
The project was updated correctly without a problem.
As a last resort we can setup a GoToMeeting and check the problem directly on your machine. Let me know what time zone you are in and your availability for the next days and I'll setup the meeting. Please note that I am located in Sofia, Bulgaria which is GMT +2.
Hope to hear from you soon.