Clarity Timsheet are filled inorder to track the progress of the project against the scheule and cost(Posted hours * Tariff).
In your organization do you plan directors and leadership team's work also on the project, and they are allocated to the project, assigned to tasks??
Another way of doing it you can hav e procedural agreement that one role is created for the leadership team and the allocation of the role can be multiplied with the rate inorder to get the cost of them on the project.
Using timesheets for leadership team would also of manual work for them in clarity which can be used for some other productive thing .