Best bet is to send your watch back to the agent. Their technician have been trained. Just like every new car model launched,there will be training provided on the know-how, do and don't.
I was told when i send in my GP for service and claim the hands, that oversea principle are not sending some of the watch parts here, due to some of the parts was not replaced and sold to outside repair shops instead, and the mentioned parts was charged to the watch owners.
The problem is, when you send to Third party repair shop, you never know what kind of parts they replaced, looking at how difficult the original parts may come by or if the local agent will just sell the parts like off-the counter! Like how we buy our car spare-parts ! I certainly don't think so.. Obviously they will tell you its Original replacement parts until you find out later.
I once send my Sinn to Germany for claims and service,they return back with my faulty replaced parts. I don't think local shop will do that.
