I would love to see ur  vim /usr/lib/lua/luci/model/cbi/cgminer/cgminer.lua  file to make sure of my ##'s

I can only get burst of Oc's for 10-15 min's then the bottom drops out and it goes down to 200-360 range no good but still stable at 218 @ 430 GH/s

I'm missing something!