Comments:
In general I never adjust date functions on a watch unless the hour is on the bottom half of the dial.
No, I don't know for sure...
But, if there is a danger zone, I expect it's spelled out in the "Jahreskalender" (Annual Calendar) operating instructions book (if the example you are considering purchasing pre-owned comes with papers).
From the manual
In general I never adjust date functions on a watch unless the hour is on the bottom half of the dial.
I really love the 1815 Annual Calendar as well, but
I think the biggest deal breaker is it being a manual wind, I would imagine having to hand wind it every 3 days to keep it going makes wearing this annual calendar a chore after a while.
Two things...
1. The popularity of the Saxonia Annual Calendar overshadowed the 1815 Annual Calendar. Many more people gravitated towards the former (Sax-0-Mat movement, iconic "Big Date" display, etc.), which was introduced first, even though the Saxonia AC lacks the one-push corrector for all calendar functions. That pushbutton on the Saxonia AC only changes the date -- nothing else.
2. I've never heard of anyone accidentally pushing a rectangular pushbutton on any Lange watch. I suppose it's possible, but I'd assume it wouldn't happen more than once every few decades.
Good luck in the hunt - keep us posted!