Modified datasource not used

I setup a test case with a DataSource loop. My source is an Excel spreadsheet, let's call it SoapDriver1.xls. Sheet1 contains 100 rows. I run the test and it completes successfully. Next, I go into Excel and modify the data for the next run, this time only 10 rows. Re-run the test and it still uses the old information, 100 rows. So, I do a Save As to SoapDriver2.xls and then Browse in the DataSource Configuration screen to choose the new data source. Still getting the original 100 rows of data! Even when I exit the program and re-run with the source clearly pointing to SoapDriver2.xls. What do I have to do to get it to reset the data source?? I do get a "Loading definitions from cache" message when I run the test case, is it caching the entire data source? Running ReadyAPI 2.1.