It seems like "logic" eludes you!
As I said... "one more time"... IT MAKES NO DIFFERENCE - none at all!
All you really need do... is make sure you get the Senns with the white/silver colored fabric covering the driver baffles - and you're certain to get... a GREAT SOUNDING SET OF PHONES!
And... as I also said... get the Senns with the black silk fabric covering the driver baffles - if you like the "veiled," dark, slow, laid-back sound of the "older" Senns.
There now... can you understand that any better?
Its not only clear and easily understood... but... it is "logical."
I am very slow... I will let you, brilliant man, to continue your good work here... I need to spend some time in some more humble and easy stuff... Do my research for multiple dimensions in asymmetrical system organization for my PhD thesis for example... I leave you with the hard stuff... have fun...