I think, a have to explain the issue a bit more. For Example: The Fullbackup have made a backup of all Data at 11/21., a have a file that was changed on 11/20. The Software is reading the the File on 11/23, but not changing it. The Incr1 is backing it up on 11/24.
The last change date is of the file is still 11/20. We have thousands of this file types.