Most watchmakers' hesitancy to perform routine poising results from a simple cost/benefit analysis.
In order to repair an errant movement, I must occasionally sort out a mangled hair spring. But I do that because I have no other choice. This is not because I lack the skills, but because the potential upside (questionable improvement in timing consistency) is far outweighed by the potential downside (of hairspring damage). & this is amplified when working on vintage Rolex pieces where replacement 'springs are expensive & difficult (often nearly impossible) to come by. Why tempt fate for what is often little or no return since factory-set poising rarely needs to be corrected during normal use. This is why I questioned your watchmaker's choice of routine poising.
I do not know any watchmakers (including myself) who poise the balance as part of a routine service. In fact, unless there is a specific problem with the balance, I cannot think why you would disassemble it in the 1st place. The only time I would poise a balance is when replacing/repairing the hairspring, balance wheel or balance screws.
The 103x caliber is a relatively easy movement for an experienced watchmaker to work on. Trouble is getting parts, since Rolex has not manufactured new 103x parts for decades. But, if you are patient & have deep pockets, they can be found.
If you cannot locate a local Rolex certified service tech, try Bob Ridley.
This is also 1 of the reasons it is recommended that mechanical movements be overhauled every 5-7 years. Keeping those wear parts clean & well-oiled will extend their usable lifespan. 1 of the parts that had to be replaced when I built my Phase 2 6542 was that rotor, due to bearing wear. Fortunately, after a great deal of effort, I was able to locate a NOS part & I overhauled the movement last year & found the bearing in fine fettle.
Ah, freedom in the good old US of A.............
Looks like some fun down there in Texas! Here is a shot of a small group of us from a shoot in WVA last month
& 1 with a watch to stay on topic (watches)
In most (not all) cases, the bezel's inside diameter is a bit too small to fit a gen xtal. So you will probably need to enlarge the inner diameter (with a Dremel, round file, etc) to fit a gen xtal.
As explained in the thread, the hour totalizer was running even when the chrono is off. As I recall, it was due to a worn braking component, but you (or your watchmaker) would need to disassemble your watch to diagnose.