I created a test
First test
Folder Contains 2 files/ 2 excel spreadsheets Office 2010
SEP11 scanned 48 files took 12 seconds to scan
Folder Contains 2 files/ 2 excel spreadsheets Office 2002
SEP11 scanned 2 files took 2 seconds to scan
Second test
Folder Contains 9 files/ 9 excel spreadsheets Office 2010
SEP11 scanned 361 files took 1:47
Folder Contains 9 files/ 9 excel spreadsheets Office 2002
SEP11 scanned 9 files took 4 seconds
So going from my test the way Office 2007 and 2010 store the files it does increase scan times.