My old pair also had channel balance issues (I bought it off someone); the replacement has close-to-perfect channel balance, however its resistance measurements are quite a bit off (45Ohm 33Ohm). I was told that that doesn't matter though, as the drivers are matched by volume.
From what I understand the resistance can matter depending on the amp. For instance, the channel imbalance is much more noticeable on my tube amp. Barely noticeably on my SS.
Either way, it is nice that a replacement is available for a reasonable cost. Not much more expensive than replacing just the earpads on my HD800 or a headband on the HD650.