The cutting act is done by a machine that responds to the engineer's real time EQ moves. It's possible to duplicate moves across regions by using written instructions or an EQ'd cutting tape (or the same stampers), however in many cases this doesn't happen.
That's really interesting, but still sort of smacks of "cottage industry".
Effectively, there is a little bloke with a tool (EQ sliders I assume) dictating the outcome as he/ she sees fit & so regional cuts differ.
Seems a bit weird that EQ levels aren't pre-programmed.
As for stampers, that's natural to expect wear anywhere you have physical processes, but even basic SPC can determine the process capability & life cycle of the stamper.
You'd know better than most, as you have actually made records , but the way you describe it sounds like there's a heck of a lot of room for variation.
Yes, that's the beauty of it! It's why you get collectors hunting down specific cuts of various records (Led Zeppelin II cut by Bob Ludwig is a prime example).
It's not quite as random or uncertain as you make out. Traditionally, 'mastering' was more a part of the manufacturing stage than it was part of the music production stage. It was/is a necessary step in the production of the physical record and in-house engineers were trusted to do the job right. This carried over into the early stages of CD production, where you find the same title is mastered differently by each region. Using the Sisters as an example, the USA CD of Vision Thing has a lot more bass than the German one, which sounds a bit dry in comparison.
Bringing things back to F&L&A, it's really great news that Sean is mastering these from analogue flats (presumably flat transfers of the mastertapes). These songs have never really been mastered properly, what with the distortion issues on the Body And Soul EP, and the generally thin sound one finds on the debut album. Hopefully Sean will bring new life out of the tapes and EQ them more naturally than before. These songs can sound *right*, one only needs to listen to Mobile Fidelity's excellent all-analogue remaster from 2011 (alas, they used the Japanese mixes). I have high hopes for the forthcoming release