When the timesheets invoice policy is set to ‘All recorded timesheets’, the invoiced timesheet lines are greyed out. When the policy is changed to ‘Validated timesheets only’, the validated lines are greyed out.

No diferenciation!

The function of validating timesheets is nice and perhaps after validation, the lines could be in blue, such as "Billable" products (on delivered qtys->blue after delivery / on ordered qtys->blue after order confirmation)