Cable makes no difference and particularly not on a planar with a totally flat impedance curve as this does. If you went from a single ended cable to balanced, it's possible the balanced output on your amp is better but it's because it gives you access to that then, not because of the cable construction.

The stock Hifiman cables are annoying, although I think they might be better now on the more recent HE1000V2s. I have replaced the cables on all my Hifimans with stuff that handles better. Sounds no different though.