That could very well be. Measurement evidence doesn't always translate into perceivable phenomena, and in this case it could be coincidence. I just thought that article was interesting because the measurements do seem to corroborate with what people usually say, at least about the 32 ohm version. As far as quality control, I also happen to know that there are some very well driver-matched DT880s out there, since every time I see a measurement of one the tracking is excellent. Clearly they put some effort into their (former) flagship reference can. I would certainly expect them to, since they cost $400 MSRP today and they're not even TOTL anymore.
I suppose the only way to be sure of any of this is to measure a lot of samples and do a lot of listening tests to see if there's a consistent difference, and that would take a tremendous amount of time and effort.