File Manager Per user du check option

it’s a quite odd feature, but it might help in some cases.
at the moment, we are facing an issue, when a hosted site has many files under the the users domains directory, each time the client enters file manager, the system hangs for him until du calculation is over.
at the moment, there are only two options for du.
on / off
set with : filemanager_du=1

this is not that good, as it will cancel du for all users, even those who don’t have a large file base stored under the user directory.

I am looking for a way to disable DU for cretin users ( maybe exempt list ).
I feel this could help others facing the same situation.