I figured it was kind of like cloning, to use a very simplistic example.
And I understand the points you're making. I guess I've been lucky with mine - the pots were labeled properly, and the DLs have all been wonderful. Haven't really paid attention to increase, but I planted my first ones in 2010, I think, so I haven't really been looking for increase yet. And the only one that doesn't really match the expected color is darker than I expected, so I have no complaints there.
(except it makes me doubt whether I really know what it is -- it should be Minstrel Boy, but it seems to be significantly darker, almost Alaskan Midnight dark).
Realized today that the scape on one of them is almost as thick as my thumb, so I'm assuming it's a happy plant
Thanks!