TheMadDruid
20635
I can only speak to your first question.
There are several models of Langes that have this feature-the 1815 U/D (which I think was first); the Zeitwerk; the Richard Lange PLM; and the 1815 RPC; and most recently the revamped Lange 1. When Lange first released the U/D the press release indicated this feature. Since then, Lange has not advertised this feature-they just let the new owner find out for him/herself that the feature exists.
Dear Dan
By: Alkiro1 : August 12th, 2017-07:15
I can answer to your second and third point. Lange probably made a subtle evolution of the mouvement recently (over the last 2 or 3 years may be. I can't tell you when exactly) which could explain your first point because with my Zeitwerk, you can notice ...
With response to 2:
By: skyeriding : August 12th, 2017-07:29
The "arming" is a little side effect of how the mechanism was developed, and my little theory is that it may or may not be observable depending on how the tolerances are set for each Zeitwerk. To understand that, we need to understand roughly how the move...