lets imagine you have excluded a folder C:\Program files\SQL and a file C:\program files\Folder\Something.exe
Scheduled scan is at 10:00 PM.
Since Folder based exclusions are processed first
SQL folder will not be touched at all.
2) coming to file exclusion. for
C:\program files\Folder\Something.exe
it will scan the something.exe first then it will compare wheater to leave it alone or take action , its excluded so it will leave it.
Thats why excluding file is like scanning and then excluding.
excluding Folder is no scanning at all..( AFAIK this is what happens)