Buddy forwarded this to me so I could clear this up. Know that any yeast that originates in a brewery is just that...were it originated from. If two different people culture this yeast and it goes in two separate directions the characteristics will be slightly/moderately different.
To the specific question:
Weihenstephan 66 = Wyeast 3333 = Wlp380
Weihenstephan 68 = Wyeast 3068 = Wlp300
Ive used all 6 yeasts. Comparing the parent yeast to the different wy/ wlp strains are much closer than to each other. That being said, both these yeasts are VERY temperamental especially the 68. Even more difficult is that these yeasts act VERY different at different temperatures and situations. Meaning that if you ferment two beers at exactly the same time the fermenter geometry and temperature should be exactly the same or they will be different products...or different enough to tell a difference. This is much more true for temp than fermenter but you get the idea. Yeasts like 1056 don't have this problem.
So, again, yeast comparisons are always close and mostly never exact...except 1056. For some reason that thing is the same no matter who uses it...