from this is how it is to exchange rates to visibly perturbed folks who have purchased watches within the past few years.
I would suspect this change is not solely based on exchange rates but reflective of market conditions.
In the past 6-7 years, there has been flurry of increases, some influenced by the price of materials, labor, and I'm sure exchange rates would fit in there somewhere as well, but I believe the market was far more influential in those actions as I believe is this latest change.
I believe the market has sent a strong message that things went too far, too quickly. Other manufacturers are talking about increases, not reductions. Patek's action may be a correction to past increases which were supply/demand opportunities which now are not there as they once were a few years ago.
It will be interesting to see how the market reacts to this and if it has shaken the confidence of Patek owners going forward.