Very interesting, if indeed cottage-industry products tend to weigh exactly what is claimed (or a bit less); whereas mainstream products tend to weigh more.
I bought a new product, a Golite Half Dome Travel Umbrella, this spring, partly because of the very enticing stated weight of 4.0 ounces. I ordered it, only to find it weighs 6.5 ounces on my postal scale. I contacted both Golite and the online seller I bought the umbrella from. Golite explained that the stated weight of 4.0 ounces was a mistake, and that it would be fixed on the website.
Now I see that both websites list the umbrella as 6.0 ounces - still understating the actual weight by nearly 10%.