i have carried out dupes under my A licence.
at my company a dupe is required during a brake change for torque rod attachment.
i hold approvals for brakes, i always assumed therefore i can sign the dupe.
i know you can only sign for your own work, but the way i see it is i am signing for my inspection, not the actual brake change.
can't think of any other dupes i would encounter in the scope of my approvals