Sellita was the main outsourced producer of ETA movements. I would assume that the machining would be top-notch if Sellita was making movements for ETA. I would posit that Sellita would focus on making movements, not designing them. Their market is providing excellent movements based on time tested, off-patent designs rather than innovation, as mentioned in my previous post. The movements are in fact interchangeable.Funny, because I’ve read and heard the opposite - precision and machining are superior on Sellita. It’s also been said that Sellita move ents are manufactured on newer equipment, which results in tighter tolerances.
I would assume that Sellita would strive to make the best movement possible, and I for one would be interested in any documentation of over-oiling. We're not talking runny XVOO here. I can't imagine a company that turned out ETA movements that never had such problems would all of a sudden over-oil movements that were in direct competition with ETA. I would think that over-oiling would be an issue with a particular watchmaker doing so, not a mass-produced movement.