Product audit
According to ISO TS Product audits should be performed " at appropriate stages of production and delivery ". (8.2.2.3)
A " dock audit " is only a part of the product audits (when the parts are ready to be shipped - the delivery stage).
If you only perform dock audits you are missing the " appropriate stages of production " part IMO.
We have always tried to perform the dock audit on the shipment when it has arrived at the customer's premises. You will learn at lot by doing this.
Check in your production area what appropriate stages are and perform audits in these areas as well. A product audit is an independent check if everything has been produced, checked, tested, labeled, identified, protected, etc....... at that appropriate stage.
Best regards,
Antoine