I've wondered the same thing. The 360S is a new board--so I really can't see why it would matter there. I upgraded by 38S to a 380S and am very happy with it--but that still doesn't answer your question. One issue could be warrantee--the upgraded versions are waranteed from the date of the original purchase of the original unit, whereas a factory original will obviously be newer and have a longer time on the warantee. The only other piece of insight I can offer is that Levinson chose not to upgrade the 331, 332, and 333 amps because it could not be done to acheive the same results as the new line: 334, 335, 336. They do have upgrades for the previous amps--but it is not as good sonically as the newer version. Hope that helps.
Levinson upgrades vs factory original
I've recently seen some ads for Mark Levinson 380S advertising that the units were factory original, not upgrades, apparently to command a premium price. Any thoughts on whether it's worth paying extra to get a "factory original" vs a "factory upgrade" for the 380S or other components (e.g., the 360S digital processor).