IWC Portuguese hand wound less power reserve

Just a simple question. I sold my 2 year old 545408 recently and the new owner claims the power reserve has dropped to less then 24 hours. The watch was sent by courier (DHL) and before shipping there was no problem with the power reserve. Could such a problem occur for example when they accidentally dropped the box or can someone think of another reason that could cause such a problem with the power reserve. Is there any way to find out what is the exact cause without examination by an IWC service department and would such a (maybe) minor problem be a reason for a full service? Any advise is welcome.

Hi Norberts
Before any conjecture, let's eliminate the obvious. I assume the new owner is familiar with the model and is fully winding it and not stopping half way?

Hi Mark,

I asked him the same question and he winds till he can't go any further ;-)

I have been told that exposure to magnetism can also effect the mechanics and so the power reserve. A good friend of mine is a DJ. Even the speakers had effect on the watch. Maybe that is the problem?

And, Norberts, you are positive the power reserve was good when it was shipped? That is a tough one; how can you tell that a change in performance of the watch was caused during delivery?

Hi Ben,

I'm sure it was doing fine before shipping. I checked it myself a few weeks earlier.

Regards
Norbert

Just a theoretical thought.

Didn´t that watch have two springs ?

Could be that one spring is unhooked, due to shock, eg ?