I wouldn't be concerned that is is taking this amount of time to come back.
The time period shows how seriously Patek and HSWA take satisfying their customers and attempting to have their watches perform with a very high standard of performance.
My personal approach to owning and wearing Pateks is a bit different from most. A + 10 seconds deviation on a new watch wouldn't lead to my sending back for service. While +10 is not in compliance with Patek's own standards, I would rather not subject the watch to a service and would prefer keeping it "untouched". For me owning and wearing a Patek is not about its absolute time keeping accuracy. However, if the watch has complications, e.g. a calendar and/or chrono function, I would expect those to work properly. Showing November 31 would not be acceptable.
That said, I know how upsetting it can be to spend a lot of money for a Patek and then find it requires an immediate service to meet Patek's own standards! Sorry you had the misfortune to experience this,
Best regards,
patekova