As far as i understood the board works with 10 or 20 chips. Not with any other number. There are 2 groups of 10 chips each. Thats why both boards are nearly the same price i guess. A bitburner x is only a bitburner xx with 1 instead both 10-chip routes enabled.
You know this for a fact? Yes the chips are logically organised in chains, but initial discussions were quite clear there would be two boards. Hence why I say, check with the man himself.
Its how the cgminer works i believe. Also, initially he tested the board with only one chip, same thing with klondike k16.