How do I set up Incremental Backups on SBS 2003 properly, when they are getting too large

Hi and thanks in advance for the help.

We are running Microsoft Small Business Server 2003 Standard at our office.  Currently I have a backup operation that isn't acting properly.  I am using the built in ntbackup program.  It is set up to go out to my boss's computer and backup his My Documents folder incrementally.  The folder is about 80 GB's in size but the backup is now nearly 300 GB's.  I am wondering if I set the attribute to not append the data and to replace it if that would work.  Or, if that would wipe out the original?  Basically I only want changes to the folder to be backed up after the initial full backup.  That is what I thought it was doing until I went in and checked the size and saw this.  It is appending every change on top of one another.  So if anyone could tell me what I need to do for sure so I set this up properly it would be nice.  Thanks

Joe

Just added a picture of what I've found.  It seems that the backup created 7 normal backups and then went to incremental backups.  Now I think I may have initially had it backing up normal at the start 1 time a week then changed it to incremental.  If I start a new backup job in a new name do you think it will fix this problem?