is it a COSC Aquamatic? how many +/- seconds per day?I guess it is all about going that extra mile getting within that standard, ironically out of all the watches I own and have owned, The most accurate auto is a non COSC watch?sure I know it is a fluke, but non the less this is borderline almost the perfect time keeper.
...can a movement been adjusted to optimized its run? and a Cosc one along the years have to been registered again to maintain its precise run?
Exactly, I have owned 11 L&B's and still have 5 of them, I would sell them all but not this Blue one, only because of the time keeping on it, if the others where so lucky to run as accurately as the Blue i would not even think twice about selling them.He said "near perfect" but it really doesn't matter since you could buy 20 of the same watch and probably not get as good.
It's just luck and the way one wears it.
If you need "dead nuts" in a dive watch, look for a good quartz.
I think so, if cosc and non-one use the same movement, many times the factory regulation is the main difference...Also, as I understand it, COSC is a certification of performance at one point in time. There is NO statement that the watch will perform within tolerance a year, 6 months, a month, or even a week later. The manufacturer is not required to re-regulate, repair, or replace a movement that is not within COSC after sale, although I hope a good AD would take care of it one way or the other if your sample clearly was not within COSC after settling down after a week or two of use.
It is nice to know that the design is such that the manufacturer has no difficulty getting a consistent enough performance to within COSC, but I suspect the COSC level of consistency is easy nowadays and the main difference is in the factory regulation.