I wish I knew why it is not working for you. Have you tried the Zeus image and put the correct amount of chips and 280 to make sure it is not a bad miner?
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
so, why X3 can use CGminer Dmaxl Zeus while X6 can only get 99% HW ?
of cause my zeus miner is fine, zeus's img works fine, minera's bfgminer woks fine too ( before is my bad to set wrong clock to get 20% HW )
but with CGminer Dmaxl Zeus i only can get 2M/each and 9x% HW, i wonder why
PS: my zeus is HURRICANE X6, power-reduce version, 64chips, 240Mhz, 9-10M Hash power, 230W on wall ,not X3 which is 328Mhz or so