Yes, for 18 months, I think there is a reason as it usually should take around 3 to 6 months depending on holidays or not (especially summer time), where it is serviced (there are some places where the volume is much more difficult to handle like in the US for isntance) etc...
However some pieces are sent to Geneva directly (especially the complicated ones), hence:
- with the pick-up by the shipping company (1 or twice a week)
- customs controls exit of the country and also before entering Geneva (can take a long while there)
- technical checking at the manufacture
- cost estimate sent to AD, which then sends it to the client who sends it back to the AD who sends it to Geneva
- overhaul work performed (considering the type of complications which can be handled only by very trained watchmakers)
- period of testing
- back to customs again (1 to 2 weeks, with leather issues if with strap etc...)
- arriving after a few days/weeks at the final destination's customs with their own regulations and checking (US with leather, taxes etc... for instance)
- shipped to AD.
This can take a long while added to the servicing time.
If you also have a specific technical issue they have to solve it and thus can be much longer.
As for the deal with your AD, we don't discuss about this kind of private negociations on PuristSPro, we remain on the only side of watchmaking passion, the watches etc.... It is very personal, depending on your relationship with your AD etc...
Cheers, Mark