Any luck with your issue?
Decided to order one, and I love how it sounds, but I also noticed an imbalance when running 4.4. It's not subtle. SE is totally fine, but 4.4 is a good bit quieter on the left channel, and I noticed the same issue you did; balanced seems to have less power than SE.
I tried both of the latest firmware files, multiple 4.4 cables, and two different headphones. One thing I noticed is that, if I play with the insertion depth (insert joke here), the left channel wakes up more completely at points, but actually inserting any cable properly results in this imbalance.
Very frustrating.