They use the same chips but different freq and lower power to achieve the results.
Clock of 240??
EDIT:
I think stock is 328 and most run it at 340.... maybe that's your problem, it would explaine your low consuption at the wall...
I take that back, I had the X3 in mind...
--ltc-debug should be --zeus-debug but it not help, still 99% HW
i think X3 and X6 use different usb chips then