Agree completely with Brandi about Excel and it's quirks (or are they features??). For some of my more difficult ETL, I've resorted to saving the Excel as a CSV before the ETL process to make sure the data will behave like I need.
Tim Mitchell, Microsoft Data Platform MVP
Data Warehouse and ETL Consultant
TimMitchell.net | @Tim_Mitchell | Tyleris.com
ETL Best Practices