Re-reading my post I guess I did, however, it was not my intent to convey there were "super units." You did a better job of stating what I was trying to.
I can't say it is the case for any/every detector company as I never have worked for one, but I know a lot of electrical components, chipsets, etc are often sourced from overseas to save money these days. It's not always to save a buck either, rather, a lot of things cannot be found domestically (at least in the case of the US.) Certain things are simply not produced here anymore. I know the quality is really hit or miss in import components, often far greater than the often stated +/- 1%. How many less than perfect components on a detectors PCB is enough to create these fluctuations in performance? Not many.