From Mike's post, I understand that the Buren movement should be at least 50hrs Power Reserve but only achieved 26 hours.
I'm just guessing, the winding could be efficient, but the storage (barrel mainspring) may not have the capacity.
I hope your Cal 1.96 has the capacity of at least 55 hours if you wore it for a 10 to 14 hour-day....otherwise you should return to Chopard.
Another point is , if the rotor is not spinning it is not a sign of inefficiency of winding. It is near to fully-wound then.
Kong