Custon precondition wont for workItem import operation.

Hi all,
I have custom attribute and created custom precondition to restrict the modification of that attribute.This precondition is applied to default role in project area
If I modify the attribute using editor, precondition works fine, but If I try to modify that attribute using import work item then I am not sure it executes precondition.
I am hoping that this precondition is applied even for workItem import as well.
Please clarify my doubt on this or am I doing something wrong
Thanks,
Kavita