CarolMN is correct.
You can borrow 2002 year points only one year ahead, which would be into YOUR 2001 use year, which for you is Sept 1, 2001 thru Aug 31, 2002.
August 2001 is a date in YOUR 2000 use year (Sep 2000 thru Aug 2001). You cannot borrow 2002 points into your 2000 use year.
One easy way to understand it is to think of Sep 1 as the JANUARY 1st of your use year, and think of Aug 31 as the DECEMBER 31st of your use year.
2000 = Sep 1, 2000 - Aug 31, 2001
2001 = Sep 1, 2001 - Aug 31, 2002
2002 = Sep 1, 2002 - Aug 31, 2003
2003 = Sep 1, 2003 - Aug 31, 2004
2004 = Sep 1, 2004 - Aug 31, 2005
and so on
You can bank any year into it's following year, or borrow any year into it's preceeding year. Hope this helps.